And this touches on one of the problems I have with deciding where to throw my money. When I look at what's available it always comes down to
samples and
triggers. I can buy just the samples (e.g., N.I.
KOMPLETE 8 Ultimate), just a trigger (e.g.
Korg microKEY,
Akai MPK88), or a trigger that includes samples (e.g.,
Korg microARRANGER, N.I.
Maschine MK2). In regards to the latter the bundled samples may... or may not... be used independent of the hardware.
At this point you get to fold in complexity: what triggers (pads, sliders, keys, dials, touchpad) are available, how do they feel, respond? Regarding samples: what's the polyphony (how realistic are the sounds), what is included in the library (Alicias Keys has only a grand piano near as I can figure out). And it helps to ask yourself what else completes the equation... how much processing power are you going to need, how much time are you going to invest climbing a learning curve?
It ain't easy figuring this shi... stuff... out.