Turbo is good for High-end Server. Mandrake is better in Desktop Appl. I don't like Core, it's like garbage. SuSE is good. Also there are some Chinese Linux system, TurboLinux 6.0 Chinese Version, BluePoint, XteamLindows 3.0, 红旗Linux, TomLinux, COSIXLinux and HappyLinux by Legend.
I suggest you use Redhat, SuSE, Mandrake or Turbo. These four are major Linux system in the world