As noted in another thread, the QM is now using the GPU when requested for Superfly as it should (although it didn't in the first release), but there are some problems still. Those problems might be failure to load some textures (affected objects showed up in white), in which case it might be related to what Ohki is seeing with Render In Background having trouble loading textures (although with a different result). For example maybe some types of paths are not being handled properly, and Render In Background gets stuck on them while the QM skips them. That's just speculative though.

The QM isn't of any use for progressive rendering though, no way around that. Personally I tend to run a quick render at a low quality to check the image, then run it again at a higher quality, but consequently I end up doing a lot of high quality renders I end up throwing away and redoing because something wasn't quite right. For me, I do that because the cancel button never works right (and didn't in Poser 11 either).