My experience with Rosegarden is that it SIGSEGV's a lot. To be fair to the Rosegarden devs, the times that I actually debugged the issue I found bugs in the underlying QT library, so I can't "blame" Rosegarden.
Still, it has to be said that I spent much more time debugging than producing music in Linux. in order to get any actual work done, I have to dual-boot and use Cubase. I say that regrettably as that is the only reason that I keep a Windows partition around and I would love to have a robust set of audio tools on Linux.