Outside of Germany, i'd say the sheerwater, or the VRX, or the liquivision or even a Heliox if your not going to do too many trimix dives in a year (hell i use my Suunto Vytec, as although its not a trimix computer, it gives me a pretty good trimix profile for dives down to 70m).
But inside of Germany, the OSTC just wins it... the support for this computer is stronger than in anywhere else in the world, and likewise the support for the others are at their weakest here...