It's really not designed for those use cases though. We were using it for a GUI and or finding was that without constraining the resource usage of the GUI using

It's really not designed for those use cases though. We were using it for a GUI and or finding was that without constraining the resource usage of the GUI using Adaptive Partitioning user-driven workloads could stomp all over the lower-priority processes. This effectively meant that a poorly-configured system would eventually trip the watchdog due to user input. QNX does include features to control this but you have to know enough about it to realize you want them. And POSIX priorities are not enough to prevent this from happening because they are solving a different problem. You might find it useful in servers where controllable latency is more important than responsiveness, but I wouldn't use it in a user-driven workload like a desktop OS without very carefully configuring it. Out-of-the box it can be very unstable.