The thing is that if you use the Computer DAW as a live-mixer and you use plug-ins, every plug-in will introduce a different amount of latency individually for every channel. So that might fuck up your timing and/or phase correlations between tracks. You can manually compensate, as Dietz doesn't recommend. Waves had compensation plug-ins, just to add the right amount of delay for the other channel(s!).
Integrated Audio DAWs do this compensation automatically with offsetting tracks.
@Another User said:
For mixing, would you recommend me using Samplitude instead of SX3 (which I have)?
I can't praise Samplitude enough, but honestly I have to say I have no experience with Cubase later than Cubase VST (which I still use for Midi).
Ever thought of a *real* mixer? That sounds actually more appropriate to your setup.