It is according to your VST demands and your computer performance. I will not be able to run Omnisphere on my current system, but I can run many of the Diva presets, but not in Diva mode. I love Bias for my guitar setups, but too many pedals will overshoot the cpu load. I run S-gear very well, but the fx in it are few…no pedals. Adding on outside pedals can also overload S-Gear. Routing is usually not a problem. Here is one of the threads concerning VST loads:,
I was using all my inputs at one time for Bass, Guitar, several vocals and electronic drums. I used some form of VST effects on all of them with no problems…but you have to be picky about the VST’s you use.
EDIT: It really boils down to your PC and what it can handle.