MBD-2
Pretty much the only permanent pedal on my board since it came out. Still am curious about picking up an MBD-1 but haven't dropped the scratch on one yet.
IME, there are some differences.
However, how much these differences are apparent in a mix, are probably negligible.
Started out with an early MBD-1, that had the clean bias trimpot, but no input gain trimpot.
I asked Jeff at Damnation Audio, and said he believes the gain is fixed at around 75% on these early models.
Had an MBD2, and ended up trading it for another 1, that was a bit newer than mine, and had the gain trimpot.
My preferred basses are G&Ls, which are typically pretty hot.
The L-2000 I have will actually clip the clean side of my early MBD-1.
With the newer MBD-1, it doesn't clip the clean side.
Setting the gain trimpot on the newer 1 to around 75% does get it to sound very similar to the early 1, but there's not as much overall output.
I had the 2, and loved it for a while, but eventually came to the conclusion that for me, it was close, but not close enough.