I love Sonic, i have no idea what you guys are talking about it, i think you guys are taking the "gotta to go fast" way too seriously, on your first playtrough you need to play the game carefully because there's a lot of traps and enemies you can't really avoid if you go too fast. However, the more you play on multiple playtroughs, once you start memorizing the level design, enemies and traps placement... you can play faster, lose less Rings, find secrets and improve your score.
So it's really like any other momentum-based platformer but in Sonic is worse because of the limited field of view and high speed. But fuck it, i love it, maybe because i played Sonic a lot as a kid and there's no "initial barrier" of frustration for me. Sonic is also pretty easy, the easiest platform game series out there, and funny thing is that i find the Mario ganes stupidly hard, like really hard, harder than Castlevania and Ninja Gaiden. I could never get used to Mario physics/momentum for some reason, i always manage to fuck up even the most basic platforming.
Also The best Sonic game for me is neither Sonic 1, 2, 3, CD or Mania. The best sonic imo is the fangame Sonic Robo Blast, why ? well, if you play this game for the first time, you'll find this game unplayable, it's really hard to get into because of the controls, physics/momentum and camera. But once you "git gud", it's so much FUN ! you feel like a god playing it:
Btw this level is extremely hard. Seriously, this game skill cap is huge, it feels like you really mastered what looked at first, an unplayble game. Plus you can be creative and take a lot of shortcuts through the levels, it feels non-linear at times.
And the music and level design is all fantastic too, the best in the series. i've played and beat Sonic Robo Blast 20 times.