Well while you sticks in the mud all cross your arms and wax philosophic about why Sonic needs a car, this game is a freaking blast.
And
I'm not
the only
one that
thinks so.
The transforming cars are a ton of fun, seeing what each character's vehicle does. Each form handles legitimately differently, the boating section feel more like Hydro Thunder than a kart racer, and the flying segments like shoot'em'ups.
The tracks are varied and unexpected. Most of them change with each lap. The Skies of Arcadia track has airships fighting as you race, and with each lap they destroy more and more of the track, requiring more and more flying sections.
I am of course partial to Sonic-themed tracks like Sky Sanctuary, but the aforementioned Skies of Arcadia track, Panzer Dragoon, Golden Axe, and Super Monkey Ball (which is only downhill
) are all great recreations of their source, and are great fun. They didn't feel the need to shoehorn all three modes into every track. A lot only use two, some are pretty much straight-up kart tracks or flight tracks. The tracks are of course replete with alternate paths, the best are the kind that let you turn into a jet a little earlier than the normal track (as it's faster than the other vehicles).
The weapons, if random, are nice and a little more skill-oriented. For instance, there is no "blue shell" equivalent that means the lead racer is screwed. It makes life a little difficult for the lead racer, but with some careful driving he can avoid it. Each character has an "all-star" mode which is unique to them (though they all involve going real fast). Knuckles busts out the Super Emerald and rockets forward, Sonic is surrounded by rings, etc.
There are plenty of modes with drift challenges and battles races and one-on-one challenges and a mode where you work together to take down a tank. These modes usually have alternate versions of the tracks (the drift challenges stay on the road, for instance). Racing with a character will earn them experience and level them up, but I'm glad that it doesn't actually make that character "better" than the others. As in I'm not in a worse position if I want to try a new character. Levels give you "mods," which alter that character's kart. Better handling for less acceleration, less speed for more boost, that sort of thing. It gives you motivation to level the karts so that you can choose how to play with each, but it doesn't make it so the kart you usually use will trounce all your other ones.
Also, the game is not a breeze. For each event you choose easy, medium, or hard. (They give you an increasing number of stars, which you use to unlock more events and such.) I play most races on medium, and still can usually only finish second or third. So far with the challenges I usually need to downgrade it to easy. A mindless racer this is not.
It has four-player split screen local and up to 10-player online races. It was the only thing I did last night and it is an absolute blast to play.
. I bought CTR back in the day, and you're correct in saying that was an awesome game, but this has a different feel to CTR. I'm not really into these sorts of games any more anyway. At least, I don't buy them, I play them at friends' places 
