Better than I expected! Reminds me of Sonic R with a bit of classic Sonic gameplay.
The gameplay is good with just a few minor flaws that are almost undetectable. Is good to go back to the racing track with Sonic and friends like we did with Sonic R. But here's a catch of this game: few characters. Where's Tails??? Guess they fixed it on Sonic Rivals 2, but at least Metal Sonic is there.
Overall, this is a good game, although kind of short. But it's great for on-the-go races and the "card-collecting" is a decent extra.
It's worth your money and, once again, it proves the quality of Sonic's handheld games is better than the other console games.
Go buy it, and enjoy!