Decent, but understandably nothing spectacular
Sonic Racing isn't all that bad, but it's not superb either. After awhile, some of the modes can start to grow stale. In addition, the game has the impression of being rather 'ordinary'. As mentioned previously, however, it's understandable somewhat given its genre (and the notion that there wasn't much effort put into this port).
Still, the game is alright. It's 'relatively' balanced, has a few fun maps/battle modes, and is generally, pretty fun most of the time. There's nothing much more to say about this game. It's basically, a decent kart-racing game that you can pump some fun out of if you have the right people/equipment/mods. Still, nothing especially spectacular, especially if the racing genre isn't anything special to you.