Not having a save system might suck... but we're talking about games that take like, 30 minutes to an hour to beat if you have any clue what you're doing. I replayed the Sonics recently and was shocked how easy the special stages were, after remembering how tough they were when I was a kid.

......

That said, in the battle of Sonic vs Mario, I say the correct answer is "Mega Man."

To be honest for me it was never about the mascots. There was actually a time I outright hated Sonic but still loved my Genesis. These days, I'm just not a huge fan of either character.... I actually kind of think they both symbolize different ways franchises can go wrong, with Mario presenting the overly-safe route and Sonic being the milked-to-death almost comic-book-like "just made up so much crap it fell apart and now its desperately trying to cater to nostalgia" route.

For me, SNES vs Genesis came down to what kind of things you wanted. When I was hugely into JRPGs, that was the major thing that made me turn towards the SNES... the Genesis had barely any that I was aware of in my teens, and even now that I know of many, they play a lot more like MS-DOS RPGs in a lot of cases (possibly because a lot of them are ports of MS-DOS games), and which style I prefer tends to depend on my mood.

These days, I tend to keep my Sega permanently hooked up, but its largely because I have a Sega CD and the crate I keep unused consoles in... well, its just easier to keep the Genny constantly hooked up. This produces an odd situation tho where I am more likely to play it than anything else if I'm just bored, and also I have come to feel I like this certain aesthetic that Sega Genesis (and sometimes TG16) games have that I don't think I see much on the SNES.... games like El Viento, Chakan the Forever Man, or Valis III which are "dark" but not in the edgy grimdark way, more in a sort of surreal way. SNES games in my experience tend to have this more nostalgic feeling for me.

Put another way, I sometimes associate games with seasons or weather, and there's a lot of "rainy/cloudy day" games on the Genesis while the SNES has a lot of "sunny spring/summer afternoon games."