regarding vcos - it's something that you have to work out yourself - listen to as many examples as possible of the ones you are interested in
I'd be tempted to buy your favourite pair of the 2 you have already chosen and live with them for a while - you may find you like th freedom too patch or you may find you want somethign that is more pre-patched (or at least organised) for you
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities