I think that a combination of a dedicated hardware arranger board (like PA80) and a computer running a soft synth is the best of both words. You get a comfortable control surface and best available styles plus the lead voices (or even style voices) may be triggered via the soft synth. I believe that on the PA80 you can set the voices to trigger an external sound source via a progam change and channal selection. So, if your VST host / soft synth combo can accept a program change you should have a seemless transition from a completely hardware arranger to a hybrid with better sounds...