grew up with a genesis in the house, emulated a ton of SNES as a kid on the family computer though. i think snes ultimately had the better game library, or at least more consistently good games compared to genesis' wild highs and lows. that said, the peaks of genesis gaming tower over almost everything on the SNES besides the absolute titans like Chrono Trigger and FF6. Rocket Knight Adventures, Ristar, Sonic 3 & Knuckles, you just can't beat them dude. (BIAS DISCLOSURE: I was always bad at mario games as a kid. COUNTERPOINT: super mario world has nothing on the flying levels from RKA.)
as far as sound chips, the YM2612 clears SPC700 easy, but unfortunately that's only in the hands of someone who can confidently operate it. we got plenty of games (especially ports/dual-system releases) with fart noise soundtracks and just had to live with that, if people let that drag down their opinion of the genesis' music capabilities i stand fully ready to forgive them for that. as much as i like samplers, being able to operate an actual on-board synthesizer is just a whole different level of control.
so yeah, just like the magazine ads always told me, sega does what nintendon't. nothing but love for the super nintendo though.