I think at this point people are hating Sonic games just to be hating on them. Sonic Colors had issues but did make it to "good" standings for me, even if I don't think Sonic Team design Sonic levels (that feel like they should be in Sonic) to save their lives.
Generations also made it into that "good" category, basically if you take out the 3D Sonic stages you get... a short but decent reminder why you still want to buy the little guys games... and if you bought the Dimps made 3DS version... well you have a great game that simply needed more stages.
I could go on about the Dimps made day stages on Unleashed and state how they were very good and I feel Sonic Team saw them and went "oh so that's how you make modern Sonic relevant and play like he's Sonic", but people would probably fight back on that one...
Episode 1 had great design, sure it had some weird patches with physics, but the run is fixed by jumping and doing a homing attack to get you going at a fast run right off the bat.
Episode 2 takes that great design and injects Sonic 2, 3, and Sonic CD. I loved playing co-op, from me and my friend not knowing what in the world we were doing, so bad in fact we could never coordinate anything, to playing with a guy online so good he made me feel like a Sonic amateur. Personally I think that's a mark of a good Sonic game, people are learning your stages and learning how to play this specific style, to get higher points and quicker times. Also the music doesn't suck (there I think I just covered all the haters).