I have a 15" Bailey on a Little Gracie II frame. I love the fact that it allows me to finish my quilts quickly, and move on to the next one. As kathy said, it's a machine with no bells and whistles; I use mine pretty much only for pantographs, and it's great for that. I've tried doing ruler work and other stuff, and just couldn't get the hang of it. There's definitely a learning curve with any long-arm -- don't expect to get it and then start turning out professional work immediately! :)
I do occasionally have frustrations with it; sometimes it's due to my own errors, and other times the machine (which I call The Beast) is just being persnickety. Anytime I get frustrated, though, I just remind myself that working on the frame is still much faster than hand-quilting, and easier than trying to quilt it on my regular machine. I definitely think having a Bailey is worth it.