Patience of a saint. I love Bioware, I like Sonic. That game was borderline unplayable. I really don't think I played more than an hour or two before returning it to gamestop (so glad I bought it used, so I could return it).
It's got issues, for sure. The enemy difficulty/reward ratio is horribly unbalanced at times. Then there's the debilitating lack of rings, which makes equipment shopping a pain. The touchscreen-only controls. Most of the POW moves (the support characters were largely useless until I got a certain Chao). The bland soundtrack, which is an insult to the franchise.
I don't really play Bioware games, but it's obvious that this one's pretty phoned in. However, there's some decent-to-good parts (the level designs, the flat character graphics, no overly annoying puzzles, a few unexpected pop culture references), and I'm more than halfway through at this point, so might as well wrap it up. I've played worse Sonic games