One of my staple pedals
351404
I'd say the pedal is about 97% the same sound as the regular sized big muff pi. By that I mean that you can get almost identical sounds as the original pedal, but some of the lower tone settings (ex: less than 1 o'clock) are not as "thick" or rich sounding as the original. However I was able to get an identical sound to the setting I like to the original pedal, for my liking.

To ensure that I was able to get an exact identical sound, I played both pedals before and after one another. I even tracked them to compare to tonalities. I could not tell a difference switching between pedals while playing or listening to recordings.

Like I said, the lower tone settings don't sound quite as good to me, but those aren't the settings I love most from the pedal. So, I got the tone I want and freed up a bunch of space on my pedal board. To me, it's a fantastic pedal for the fuzz that I love.
1626208
This pedal worths a 5 stars with no doubt.
Only one thing I want to mention is that the Velcro that's in the box is absolute crap; not that it doesn't stick on to the soft pad, but the tape on the other side of the velcro is just too weak to hold the pedal on the board.

Hence what you're ended up with is enough strength to hold the "Velcro" on the board, not the pedal.

It is of course a trivial issue, but should be taken notice if one would like to keep the pedal in almost perfect condition(like me) and not have tape residues on the back of the pedal
15223
I'm a big fan of this pedal. Thus is my second. If you like the Foxx tone, you will dig it.
2019703
I must have bought my DS-1 twenty years ago, and it was long neglected, but when comparing all my pedals I decided this was the only one that let my playing subtleties show through. Many pedals today are obsessed with ultra high gain, which makes you sound anonymous. Here, you get distortion that begins with a mild crunch near to your clean signal, and moves to a searing sound. The tone knob goes from a dark thick sound to a bright, thinner and progressively less bassy one. I am slightly amazed at how many good combinations I can get by adjusting these two knobs, and moving from the neck pickup to the bridge on a Strat. Try Tone = 11 O' clock with Gain all the way down, or Tone all the way down with Gain = 1 O' clock; two very different and useable sounds. Sometimes I wish the pedal had a little more bass response to it, and you can forget rich tube-y harmonics, but then the idea is to get a brighter, more cutting sound, so I can't really complain. I play rockabilly, '50s style rock 'n roll and Hendrix/Trower type stuff, so this suits me just fine. (And it's a standard platform for modification if you want to experiment). Recommended.
2811180
I've had this pedal a few weeks and have found it to be a great addition to my board. I play electric bass through it and - as reviews and company literature says - it sounds a bit squirrelly if you go below C on the A string (or the equivalent on the E string), but otherwise it sounds great. If you don't play with even attack it can get odd-sounding too. I can play fairly evenly but I still use a pedal compressor before it and my rig has a rack compressor - which helps in loud live situations. The jazz organ and the cathedral organ sound are favorites but they all have something to them. I think it's a great pedal.
4112532
I do a lot of alternate tunings on my live gigs and really appreciate that I can hit the pedal and it takes my sound out of the house system as I do my thing. That feature alone is worth the price of the pedal, plus it's a quality unit as you'd expect from Korg. Love that it's fully battery powered.
2204869
This pedal should provide almost any sound I need to use, plus a lot of settings I'll never touch unless I want to get yelled at by the band (lol).  Battery life seems to be pretty good so far and the looper and rhythms are fun to play around with.  I've still got to learn how to move patches around so I can have them in a usable order, but so far so good.
3521825
A great pedal for a decent price. I'm running it direct into my recording console, and it's really versatile. A few minor adjustments give you a wide range of distortion, from very subtle accents on a clean tone, to a thick, heavy crunch. I really dig it!
1917851
Nice subtle distortion that are mostly not available with over overdrive pedals. I use it to give a slight tinge of overdriven amp sound. A very good addition to my pedal collection.
3485796
I use this pedal as more of a clean boost with just the tinniest bit of crunch tacked on for a bit of extra character to whatever it is I'm doing. I play church music which goes from some pretty high gain stuff all the way to really soft stuff. This pedal typically stays on the whole time.

This pedal just works really well for my purposes. I have a bunch of different guitars and I play whatever guitar it is that I feel like for that particular day and this pedal... For $50 it's one that you really can't pass up in my opinion.
2136490
Have had no problems, had it for months and use it almost every day. Will probably get another when I get more pedals.
4306533
Awesome wah! I love the versatility of this pedal to having it sound strong and trebbily to having it more subtle and bassy, and everything in between. It sounds great when im shredding with it, and when im playing funky, mellow blues.
620012
I change up my board often depending on the gig and use these any time I have two pedals of the same size and shape next to one another. Massively helpful for saving real estate and almost necessary for those pedals that put the 9v jack SO CLOSE to the 1/4" jack. They don't feel cheap at all to me and look great. Go for it.
1196111
This pedal is really good, maybe even great. My only thing would be that the toggle could either be a) removed from the design (just have it default to 'warm' or whatever, or b) the toggle could be more sturdy (bigger). Even so, that's just a nit. This thing sounds great. The thing is though, it might not be a 'mad' drvier, but it sure has a lot of great character. It's quite smooth, with some great overtone action when you want to make it.
962091
I love these pedals.  They're functionally identical to the cheaper models, but much lighter.  It probably doesn't make much of a difference, but if you're counting grams these are great.

I love that they don't spin when I'm trying to clip in.

The machined edges were a bit sharp out of the box, so I immediately took an emery board to them.  I'd rather have my pedals scratched up than my shins.

The large surface is sufficient for riding with regular shoes, unlike the race style pedals.
725978
This pedal is great!  Having a boost and an overdrive in 1 pedal is just what I needed.  I have tube amps that sound good and this overdrive really sounds good with them.  The neat thing about this pedal is if you have to play through a solid state amp, you can set the overdrive up for a good sound for rhythm then kick on the boost for a lead.  Works great, I'd recommend it to anyone
3247573
After much research into all sorts of clean boost options, I went with the MC401 MXR Boost/Line Driver.  My decision was partially based on other reviews, partially on my experience with other MXR pedals, (Carbon Copy Delay and Super Comp compressor) which I've found offer great tone, solid build, and great mid-priced value.

My only complaint is the placement of the DC power jack, which is adjacent to the signal input jack on the right side of the pedal.  (I use both Hosa and Planet Waves right-angle 6-inch patch cables, the Planet Waves fit, the Hosa doesn't.) Easy enough to deal with: Just make sure your input jack is relatively small.  (This is so with my other MXR's, so I was prepared.)

I'm playing through a late '70's Fender Twin Reverb, which is legendary for it's big, clean sound - and just wanted a simple single-knob clean boost for leads.  This pedal kicks up the volume with no apparent loss or coloring of tone - just more of whatever I've put in front of it.  The Boost/Line Driver is the currently the last thing my signal is going through before hitting the amp, which allows me to keep the outputs on my other pedals - which are very few - at relatively low levels.

Bottom line: One nice clean boost and one very happy guitar player!