This article is from the Amiga CD32 FAQ, by Stuart Tomlinson with numerous contributions by others.
A: It's completely compatible with the C= CD32 joypad.
Some good things said about it are that it's shaped like a Megadrive joypad, the diagonals are easier to get to, it feels less delicate, it has turbo and auto fires, and it has a slow motion button.
Some bad things said about it are that it's shaped like a Megadrive joypad and the diagonals are more difficult to get to.
Obviously a bit subjective.