I've always used Madcatz sticks and there is a new one coming out at the end of May for $200, but for MKX, I'm not sure it's worth buying a stick. Atleast from my perspective. However, since USF is coming out for PS4 soon, I guess it would be a good time to pick one up anyway. If you need one now, I would agree that either of the new Hori sticks would work. As for XBOX ONE, I would say that the only one I've seen and played with is the Madcatz Killer Instinct which is nice, but it's also $300. Don't know about any others.
Looks interesting, but I will definitely need to see more. I'm wondering about the variety in the game. If the crowds are based on venues and there are only a small number of venues, I think it could get old very fast. Also, I'm wondering how responsive the guitar controller is. It's hard to tell in the videos.