To me Cubase SX 3.1 also is rock solid.
Earlier verions had problems with a cpu performance higher than 50% (dropouts).
Now I have no problems above 80%.
That?s great (although I need a better System).
And together with the TI it?s total fun (ok. when it will work correctly...

)
SX 3.1 and TI is best way to go!!!
MarcTale