I personally have a couple of Sonic games, though I like Kid Chaos more. It plays just better, smoother. And why think people Zool (2), Chaos Engine and Ruff 'n Tumble do not play smooth? :-? These work perfectly smooth on my plain Amiga500.
And maybe the Megadrive/Genesis have better sound chips, I think the Amiga the Amiga just sounds better.
Really, the only drawbacks of the Amiga is that it cannot do texturized 3d, and the juggling of floppies. (But then there's the CDTV, and the C2P in the CD32).
I got quite a collection of computers/consoles+games at home, and I play the most with the Amiga500, the C64 and the Dreamcast.