There are two aspects of RMS that seem to be crash prone based on what I have seen.
One is HQ Server - it's memory management has always been sort of shaky, but this was the biggest focus of the 1.3 release. I don't think that 1.3 has been in the field long enough to know it it has fully corrected those memory issues, but performance and stability of HQ communications were definately the priority for that release.
The other is hardware. Most XP computers don't have OPOS devices connected to them, while most RMS systems do. MS might be able to do a little better in their use of devices (like claiming them on demand instead of on start-up), but the stability of the drivers is on the equipment manufacturers.
I really can't think of a single case I've seen where Store Ops crashed windows. HQ Server has been known to lock a machine up to the point that you can't reboot it without hitting the power button, but that can be managed.
The last roadmap I saw has a 'major' release about every 6 months - that's a Service Pack this summer and a 1.4 near the end of the year. What I saw did not have a RMS/POS merge, but that has to happen somewhere down the line - as of right now, it appears to be several years out.