No, no real problems, other than not being familiar with the interface. It's definitely stable. If you're familiar with Mainstage, and like it, I'd definitely suggest getting it. My biggest problem with it was that I'm not familiar with the interface, and it was late.
I haven't tried linking Ableton to Mainstage. I've been using Ableton by itself, with my BSP, my Volcas, and an iPad running Lemur as a control surface. That's super fun - but I've been having issue when recording midi into Ableton from the BSP.