I'm a BOSS fan, and I try alot of them out.
Here's my opinion on the DS-1, MT-2 and MD-2
The DS-1 is a classic distortion sound that u'll get. Akin to the old days Led Zep, Pink Floyd, UFO, Queen type of sounds... It's a little on the high side, with slight crunch. When set at mid-levels, sometimes sound like an OD. If u are thinking of this, you might wanna try the DS-2...upgraded. The DS-1 is really really old.
The MT-2 on the other hand is more modern. Nice sound with 4 adjustable eq levels and a overall distortion control knob. The controls mean you can get alot of contemporary sounds from this beast. Pump up the bass, lower the mids, you can pull off a linkin park. Moderate the highs and lows, and push the mids, you can get the 70s brit rock sound. So, over all, very versatile piece of metal.
The MD-2 is on another spectrum. It's no versatile. It's a very specific piece of machinery. It's ONLY for nu-metal or punk metal..or those linking park stuff. Very heavy low end, super chunk sounds. Some people say it sounds like MUD, but u need a good amp to pull this off...and a good guitar. If the DS-1 is a hot rod cadillac, the MT-2 is a modern Ferrari...this on is a 18-wheeler freight truck. All brute power and nothing else.