My own perspective on some of the most recent Sonic games.
Sonic 2006. I got it in November 06, (originally, the reason why I got the X360) and my God, it was awful. Basically the game is glitched and has very long loading times (not even PS1/SAT games had those loading times). The story, don't get me started...
Sonic and the secret rings. Just unplayable. I understand Sega was experimenting with the motion controllers but they should have included a regular controller option.
Sonic and the Black Knight. Another Wii sword game. A meh kinda game. If you wanna end up with a sore arm, go ahead.
Sonic Unleashed. I got the X360 version. I like you can pick the japanese language with subtitles. It's like having two games in one. The hedgehog stages are nicely executed, the werehog stages make you think, the button mashing can be relaxing. Give it a shot, although not on the priority list.
Sonic Colors. This is a highly underrated game (maybe because of its name and because it was a Wii exclusive). It is a shame they didn't make it for the HD consoles. Great gameplay, well inspired stages, great atmosphere overall, multiple control choices.
Sonic Generations. Just get it.
Sonic Lost World. It's ok. Feels a bit awkward to control but you get used to it. Regarding perspective and cameras, somehow it is what Sonic X-Treme may have been. Not bad, considering the anemic selection on the Wii U this is one to get for the system.