Good Sound Quality, but Cheap Construction
934768
First of all, the sound quality is really good.  Sometimes headphones can slightly deteriorate the sound quality, but I can hear every last note perfectly with these earbuds.
Unfortunately, I don't think these are worth the price.  The quality of the earphones is very cheap.  Mine have not broken yet, but I've only used them a couple of times.  They just feel like they are going to break apart, which makes me very hesitant to use them a lot.  The pieces just feel a little loose and wiggly.  With even the slightest amount of wear, they could come apart.  Good, high-quality earphones should feel sturdy and be able to handle a little wear.  These Brainwavz earphones just don't make the cut, which only reinforces the idea that you can't trust products that use a 'z' for the plural form.
My recommendation is to pass on these earphones.  Maybe mine are just slightly defective, but I don't think it's worth the risk.  If I'm going to buy earphones that break quickly, I would buy them from the dollar store so I don't waste a lot of money.

I received this product at a discount in exchange for my unbiased review.
525545
Sound quality and fit are decent. The folding design and carrying bag are excellent. Using these for phone calls is a bit of a joke. As I was intending these to be primarily used as headphones I didn't mind.
 However, the second time I charged these, the USB port folded up and bent. The construction of the charging port is terrible. As this is the part that likely will get a lot of wear you'd think the mooring would be a bit more sturdy. I tried straightening the pins and they caved in. Soft, soft plastic. Not something you want to plug a metal connection into.
  I tossed them out and bought a set by LG:

<a data-hook="product-link-linked" class="a-link-normal" href="/Kinivo-BTH220-Bluetooth-Stereo-Headphone/dp/B005LKB0IU/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">LG Wireless Bluetooth Stereo Headset</a>

  and although I haven't used them much yet, they are light-years better.
3362571
The package arrived on time and was about as I had expected reading other interviews.  The case of the Vox AC30 is cheaply formed, which is a shame considering that this device is convenient for just playing around with headphones. It would not take much additional cost by Vox to beef up the case construction and the controls, which they would pass on to the consumers, but two or three dollars would go very far in high-impact plastic and some better quality pots (controls).  The sound is okay, and I am good with it since this device is for me to play around with a few licks on a lazy afternoon on the back porch, or some place I cannot access my systems and don't want to drag even a small amp around (which will have only marginal sound anyway).
2982107
On the upside, the package is nice and compact. The sound is pretty good, and the rechargable plug setup is pretty clever.

On the minus side, the built-in 1/8" plug is a bit short and the volume controls only go so far (it never quite even gets to the loudness of my MacBook Pro laptop, which isn't saying much). Worse: the rubber surrounding the connector at the base of the jack frayed and exposed the wires rather quickly, rendering the audio connector useless within a matter of weeks.

So I switched to the standard 1/8" jack at the side and bought a good connecting cable. But even that connector wore out after 6 months of use, shorting out and requiring me to buy another speaker.

I wish I had purchased something else -- even for more money. The construction/materials just do not hold up to wear if you use it somewhat regularly.
423150
These headphones have good audio quality but the construction is really bad. Its been just 2 months with very little use ( I wear to the gym probably an hour 3-4 times a week)the headphones have started to come apart. I would not purchase these again.
3093450
This little gadget paired quickly, works well, and sounds great. The design lets you plug in your own earphones if you want, though the ear buds that come with it are pretty good.  Unfortunately, the clip on the back is so cheap and flimsy, it's not possible to fasten the receiver securely to clothing. Even leaning over will cause the device (which is quite small) to fall off your shirt. OK for driving, not OK for any kind of exercise.
4174931
The sound quality is good for the price and the battery life is excellent.  Unfortunately after about a month of use the power button broke so I can't turn them on anymore and now they're junk.  To me that's not acceptable for the limited amount I've used them.
1891838
These are probably the best sounding headphones you can possibly buy for this price. My only qualm is the build quality. I'm on my second pair of these, because the cables are very cheap and wear down with constant mobile use.

You would think they'd do something like the beats cables, but no - these are really cheap and lame cables and connectors. They should be wary of offering such good headphones with such poor build quality. Mobile headphone use is especially hard on the product, which means they're not thinking about their users and how they use the product.

I hope they see the light and actually create headphones that can endure the rigor of everyday mobile use, these headphones and their customers deserve at last as much.
4080102
This is a good, budget or spare Bluetooth/stereo-jack headphone. It'll deliver great sound, and will last with reasonable handling - but don't drop them on a hard surface though. I did, and one of the control buttons broke and I had to buy another pair. Phone calls go well in places without a lot of ambient noise; the mike is on the L side w. the controls, so you must wear them that way to use a phone, else the mike will face your back and not pick up your voice. They look real expensive, too, but the trimming & paint wear easily so put 'em in a case if you want them to stay floss, don't throw them in a backpack.
3956737
These headphones sound great, but the wire broke off of the headphones rendering them useless. The construction, not so great but the sound and technology used to make them noise cancelling is where they put their money into when making the product.
4097012
Decent audio quality for the price, but cheaply made. The band that goes across the top of the head snapped in half after only two months of use. In-headphone language randomly changed to Chinese after a month of use.
3357343
The Good: The sound quality is very nice. The noise cancelling works very well. I have used these to play music in a noisy open office environment and they really help me concentrate on my work. The price is reasonable, compared to Bose that honestly do not look much better. I doubt most people can tell a difference in sound quality.

The Bad: Within the first few months the switch to toggle the noise cancelling on/off became faulty. It eventually lead to the noise cancelling not working at all. I had them replaced under warranty. The new set is starting to do the same thing. Also, the plastic construction quality is very poor. They seem like very cheap plastic and the first pair broke when I lightly dropped them. The headphone pads started to fall apart and the foam is becoming a mess.
4573403
I bought these from my local Walmart a few months ago. I bought them to listen to music at school because I don't like having to untangle earbuds every time I want to use them. The cord length is not too long, not too short. The build quality is where the 3 stars comes in. Cheap plastic and okay ear muffs makes these kind of uncomfortable after an extended period of time. However, they have a great sound for such cheap headphones. I also purchased a vintage stereo system in the summer, and I like my stereo amplifier with the base turned all the way up. When I went to go convert my vinyl to MP3, I did not had to lower the bass settings on my stereo amplifier because the music started to become distorted. I got about as close as I could to the bass level that I get on my stereo amplifier, and my vinyl music now sounds really good with these headphones! For 20 bucks you get poor build quality but a pretty good sound for the price.

I recommend these to anyone looking for a cheap pair of headphones with good sound. However, you do not get the ear and head comfort pads of higher quality headphones.
2396958
Sound quality is quite good, but it unfortunately broke after a few months of use.
3698377
Koss sub-$20 phones.  Well constructed, comfortable phones, but noticeably weak mid-range and treble that is fixable by boosting upper frequencies with an equalizer.

For me, headphones have basically two value-related components:  sound quality, and physical construction.  In my experience, most low-price-point phones, such as these, produce an acceptable sound but have poor construction, weak chord attachment, flimsy plastic adjustment points, etc., and are ready to fall apart very soon.  With these Koss phones, that typical situation is reversed:  the construction is good, the sound not so much.

The construction is way better than the competition.  These are sturdily made and should last a good while.  The earpieces are plenty large and the headband works with my large head without being too tight.  One reviewer dinged these phones because the over-head
support is cloth/plastic.  But I see this as a big plus because a very common problem with budget phones is that the foam on the earpieces and headpiece disintegrates quickly leaving a sonically functional set of phones that is nevertheless useless.  This set won't have that problem on the headband, but the earpiece coverings are standard foam with cloth/plastic covering so it remains to be seen how long those hold up to being pulled on and off, and subjected to the inevitable skin moisture and oil.  But, basically a well constructed set of phones.

Sound-wise, though, its a different story.  While the bass is good, and theres plenty of it, the mid-range and treble are weak and the sound is flabby, as if heard through a wall.  I don't expect miracles in budget phones, but these have  unacceptably weak mid-range and treble out of the box. The treble roll-off is very pronounced and the sound lifeless and flat without enhancing the mid and treble with an equalizer.  This is a flaw in the way the phones are set up at the factory, not a limitation in the drivers, because I can get them to produce a very good sound with the equalizer.  Though I was able to get a good balanced sound by fiddling with the equalizer settings on my source, that's got its own set of problems:  you have to do it every time and with every device you use these on.

Final note, some reviewers complained that the chord was too short.  I was expecting something 18 inches long, but its three meters; plenty long enough for me.

So, four stars:  much better construction than the competition, capable of very good sound for the price, but you have to tweak the EQ.
1568077
Pretty good sound quality. One ear was always a little less audible than the other. Biggest issue is how fragile they are. Even keeping them in your pocket the sockets would pop out and the only way to fix them is while super glue, which you have to get the angle exactly right or else the headphones won't fit in your ear again.
4713409
As many others have noted, these things fall apart.  Just this morning on the bus, the little "capsule" that contains the microphone fell apart.  Fortunately, I pushed it back together and the headphones still work.  I plan to superglue it together when I get home and hope for the best.  Because the sound of the headphones is great.  The sound quality of the microphone is terrible, but I don't use that feature often.

Conclusion:  There are probably better choices out there.