Now I am not the biggest fan of the Sonic franchise. Especially when it comes to his racing games. Apart from this, Transformed and Riders: Zero Gravity I think the Sonic Racing games at best were mostly mediocre and at worst, a steaming pile of trash (Looking at you Sonic R....).
Sonic and Sega All-Stars Racing was my first Sonic game back in 2010 which I played on the Nintendo DS. Over the years, I would put a crap ton of hours into the Wii version and now recently the PS3 version. The PS3 version is the one I will focus on, though I will look at the DS/Wii versions too.
As you can tell from the title of the game, this is a racing game that released in 2010 for multiple platforms. The aim of the game is to use items as well as your driving skills to reach 1st place. There is a standard Grand Prix mode, VS Mode, A Mission mode which has you going through various missions as a set character, Online, which allows you to race/battle against others and a Shop, which you can use any SEGA Miles gained from racing to unlock courses, music and characters to use in the game.
You can also improve your license via lifetime miles which are also earned via racing/missions. This will change the colour of you license plate, which is essentially your saved data.
If you've played any of the Mario Kart games, specifically Mario Kart Wii, you'll feel right at home with ASR. The game plays like a Mario Kart game, tricks/items and all. The game's main gimmick, however, is the All-Star Moves. When a character is doing badly and obtains that All-Star item, they can proceed to wreak havoc on the other players. These moves are based on the special moves from each character's franchise i.e. Super Sonic, Billy's Giant Egg etc.
The DS version of ASR has differences. For one, there are fewer songs in the game as well as some arrangements made to existing themes like Super Sonic Racing. Characters like Metal Sonic do not exist and the Zobio/Zobiko pair is now just Zobio. Also, I feel that earning Miles is much easier on the DS version than the console version. The DS version of ASR is a fine game, worthy of being the competitor to Mario Kart DS.
The Wii version retains the same content that the other console counterparts have, though I do believe that Metal Sonic isn't playable in that version either. Like various other games, you can play as your Miis saved on the Mii Channel.
Sonic and Sega ASR will remain one of my favourite Sonic games of all time as well as the best Sonic Racing game. This game boasts a substantial amount of content and provided me with the same amount of entertainment I would get if I was playing a Mario Kart game. If you have not played this one, give it a shot. I highly recommend this game.