Russian Big muff's are great bass pedals in general iv found, and iv gone through more than most
Best for me was the Civil War Big Muff, the blue/grey russian one. Was just better than the green muff and embarrasses the black. The painted black one mentioned is pretty much the same as the later green ones, just black with 2 screws on top. The 4 screw latest edition is the weakest, but still very usable on bass. . The rams head is a good one for bass, and probably the only american one i would recommend. I did have a 70s op amp model that was okay, and sometimes you can get them cheap.
The only muff i havn't owned is the original triangle one and the earlier no screws on top green one, that latter i imagine to be very similar to the civil war.