How hard is it getting used to stick? Might get one, or just a fightpad
It's not terribly difficult but unless you just think it sounds fun, I'd stick to pad. The exception being you plan to play KOF or some older fighting games enough to warrant the investment, and even then a pad will get you by. SFV is definitely built with pad in mind and I can't see any benefit to stick. I play stick and actually practice with a pad occasionally in the hope that eventually I'll just make the switch to pad permanently.
SfIv and some older games will absolutely benefit from a stick.. doing the buttons 'motion' of Blanka's electricity, Decapre's rapid daggers, Chun's legs, Honda's hands, etc etc, is a lot harder on pad when you need to combo them (just doing them raw isn't bad) but stuff like Decapre comboing low forward into lp rapid daggers is a real BITCH on a pad. So is plinking. So are qcf hcb moves like you see in KOF. All of these are doable on pad, just much more difficult.
It's all up to preference though. I started playing sfiv on pad because that's what I played MKX on, but kept reading stick was way better. Got a stick and kept playing MKX on pad, but learned sfiv on stick, now to the point that the game feels really weird to me on pad.. that said though, when I play pad I feel like I react faster and have better movement and control.of my.movement. I feel so strongly enough to slowly try to transfer TO pad play. Conversely though, i feel like stick feels more.fluid and natural on offense and combos and such. Purely subjective , just my personal interpretation of it.