pc with ray2fix is the best if you just want stock rayman 2 in 1080p with gamepad support and button remapping
dreamcast port is widely considered to be the "definitive" version of rayman 2 as on top of arguably looking and sounding the best, it has an actual overworld hub instead of the simple level select screen and minigames in it but you have to emulate it if you dont want it to be a blurry mess and it's a bit buggy
the ps2 version is basically a remake with different graphics, modified (longer) story, more levels and english voiceacting instead of the banjo kazooie nonsense-speak that's in all the other versions