Personal: got the QNX/RTP stuff loaded and working last night. I haven't done much with it yet, but I already know I like it better than anything I've gotten running on Linux. Photon makes X look like the buggy, bloated hack job that it is. I haven't made much use of PhAB yet (the GUI-builder for Photon), and reports indicate it is still unstable, but I'll probably play around with it a bit tonight and see what it's capable of.
I've always been a fan of OSes like VxWorks and QNX because they seem so much *cleaner* than other architectures.
I've been using QNX4 (the previous version before RTP) for the last year + 1/2. It's not much cleaner than Linux, it just has less functionality. And oh, the bugs, don't get me started ;)