Not really dimmable, They fickler in the dim setting ...
926133
Not really dimmable, They fickler in the dim setting and then burn out rather quickly.  Mine lasted a few months.
2851605
Might work as a mood light, but way too dim to actually light up even a small space.
3460325
I have several Hyperikon dimmable LED lights in my home.  I love the ones in our dining room chandelier.  Unfortunately, this product is not one that I love or even like.  These bulbs were far more dim that advertised in my dimmable fixture.  I had no choice but to return them and buy something at Home Depot on my next trip there.  Quite disappointing.  I rate it two stars because they do turn on and dim, but perhaps that's too generous.
549143
These aren't nearly as bright as they advertise and get dimmer if you leave them on. After an hour, I could barely even tell that these lights were on.
633116
I previously bought several Philips LED lights and found out that my Lutron dimmer switches (although LED compatible) did not support them (rapid blinking).
I decided to give these a try and so far, they seem not to have the same effect.
2509427
Package clearly states dimmable, but this is wrong! They human as bad if not worse than the halogen bulbs, but these flicker and shut off on there own.  Worse light purchase I have made in a long time.
2624412
Guess I should have read more of the fine print, but so you know these are NOT dimmable.  Otherwise, I have 3 identical ceiling fixtures that I tested these xenons out against the normal halogens, special order led bulb.  For brightness and clean, white light, these were far and away the best.
4815799
I'm not going to suggest that these aren't actually brighter than a standard incandescent 1156, but they aren't nearly as bright as I would have hoped, and they are definitely not as bright as similar LED lights.  I was misled by the large yellow patches suggesting that they employ larger LED elements.  Upon testing I determined that these lamps employ small LED elements essentially "potted" in a yellow compound which does nothing to make them brighter.
2071247
Although they give off adequate light, they are physically as large as a standard 60 watt bulb.  They don't fit within the lens housing of an over-the-range hood.  I have had to leave the lens housing off for these to work.  Nothing in the description states whether they are dimmable or not...they are NOT DIMMABLE...you have to enlarge the photo of the box in order to see that they are not.
What Sylvania should be making is a 40 watt APPLIANCE bulb size in an LED format that is dimmable.
237300
These lights aren't very bright. They're more for ambience. Also, untangling these was a real pain. Took me a couple of hours - be forewarned!!
4877758
The bulbs are bright and they work great but, they are not dimmable as described. I have a 3 way touch lamp and they only work on the brightest setting and will not shut off unless I unplug my lamp. I'm not very happy about that. Now I have to find a new lamp that these bulbs will work in. That is the reason for the 3 star rating. Amazon shipped these to me very quickly as usual.
3979620
Tried to replace halogen MR 16 in a living room, but gave up because there are only a few ( 4-6) discrete dimming levels and the lowest is still very bright, so they are unusable.
I will use them for full-on landscape lighting instead. It is a bummer that I specifically looked for dimming bulbs, and paid more for these, only to be disappointed by their poor dimming performance. Two stars because they actually work full-on.
Buyer beware.
3537346
These so called dimmable LEDs are probably decent dimmable lights, assuming one can find a LED dimmer that actually works.  I purchased some Lutron LEDs here on Amazon (Lutron Maestro MACL-153MR-WH) and found that they're not compatible (even though some reviewers indicated otherwise) and will not function at all due to the feedback from the LED bulbs.  I also attempted to use Leviton dimmers that I had been using with incandescent lights, but the dimming was only down to about 70% brightness and the flickering became intolerable.  So what I've done is buy a lot of these BR30 dimmable LED bulbs that effectively only work as "non-dimmable" bulbs (they're great "standard" LED bulbs!).  Please beware.  I hope any of you who buy these has better luck finding dimmers that will work.  If you do, please let me and others know.  I've got a house full of these "non-dimmable" dimmable LEDs!

Update:  Received full refund with absolutely no hassle.
2335871
They dim horribly. I tried them with two different LED dimmers and got all kinds of strange results. When hooked up to a regular light switch, they are very bright, so you would ponder using a dimmer. What you'll get are things like:

1. The lights never reaching that peak brightness at max on the dimmer.
2. A very small variation from minimum to maximum, regardless of trim, calibration, or whatever your dimmer does.

We were very disappointed because the peak brightness is too overwhelming, but we cannot cut them back to an appropriate level.
4911502
Barely dims the Feit LED bulbs I got at Costco. Bought Lutron dimmers and they work great, so it's not the bulbs.
3360628
Bulbs look great and the light color is great too, but they are not dimmable. We had an old dimmer for incandescent and that did not work, making them flicker.

We then installed an LED dimmer (Lutron Caseta) and the bulbs wouldn't event answer to the dimmer on/off, lights would just stay on at say 50%. Never mind dimming up and down. As a test, we substituted a single bulb with an incandescent one and we were able to dim.

Solution was to substitute one of the 15 Oak Leaf bulbs of our chandelier with a more expensive LED dimmable bulb by Feit Electric of similar appearance and all of them can now dim.

So yeah, the problem are the bulbs, and the fact that LED lights manufacturers didn't get together to create a standard. So anybody can claim to make a "dimmable" switch or bulb and then shift the blame to the other tools.
2538248
Description says Dimmable.  These are not dimmable.  They turn to strobe lights when you put them at anything other than full strength