mine using M-audio keyrig 49
USB powered
velocity sensitive...that a minus for it..but its cheap

with a DAW n VSTi..no problem at all
just using it with OPCODE SONICport..but still no midi i/o

with VSTi, u can have any sound u wish with a MIDI controller

Bro,its a midi controller..it produce general midi and converted into sounds module or VST u want to use

yes..mouse can do..but the VST wont be able to be controlled by mouse..it cant produce MIDI
mouse cant do the pitch bends and the sustains needs

the feel it self plays a major things..how do u want to produce a chord or harmonics thinggy if those mouse just have only 2 or 3 clickable button?how about those octave u want to use

yes a VST need to buy but there are a lot of free cool VST or pluggins too
choose if it fits your needs