Unlike what most people say, I say it's a fine game and deserves to be mentioned alongside other Sonic classics.
Graphics: The isometric view really reminds of Super Mario RPG, since it uses the same view. Sprites are prerendered, and the scenery is beautiful, I really have nothing to complain about with the graphics, and while they were improved to look shinier on the Saturn version, they still are great and don't really need to be changed. 8.5/10
Music: The music in this game is probably the best Sonic soundtrack, and still is, next to Adventure, Heroes and S3K. No surprise though, since it was composed by Jun Senoue, who also composed Adventure, Adventure 2, Heroes, Shadow, and other more recent games. 10/10
Gameplay: Gameplay isn't the same as what we're used to in terms of the Genesis/Megadrive classics, and really doesn't seem like it would fit in the Sonic universe, but surprisingly, it doesn't get boring fast. I generally take a break from this game after about an hour, and usually I do take breaks from a game after an hour and a half, so for me it's not all that boring at all. Control is good, though Sonic tends to slight a little, and the control can be rather wonky your first time playing, but it should improve by the third or so play. 7.5/10
Really, try this game out if you can, and see if you enjoy it. I personally do, and 7/10 people probably won't, but just give an honest try and don't say you hate it because most people do.