They're the most powerful, flexible MIDI controllers out there. It's hard to imagine a scenario they could not handle. The new X Series looks amazing, it's supposed to be released in August. The concern you always hear is support, but it seems like people get good results by using the ticketing system (don't bother emailing them or posting on the forum). I have not had to use their support since I was setting up my original LF Jr. years ago, but in fairness I have to say they were great at that time. I do wish they'd respond to emails though. Not sure what's the point of having an email address if it's going to be a black hole.
EDIT: I just asked a question about the X Series through their ticketing system and got a response within half an hour...so that's encouraging.