Given that I never had any really major problems, I'd be fine with sticking with BB OS hardware provided it's not completely abandoned until QNX is well mature enough to completely take over as a the primary OS. Could you see switching to a BB 7.5 or 8 (whatever the next OS7+ devices will be) device should one come out during QNX' first year or two on phones? What would be your reasons for not sticking with BB OS if you had the option to go either way?
We'll all have to wait and see what the first QNX phone supports. For example, there have been some theories that the first one won't support BES - which would be a non-starter for many people.
Also, how many applications will be available for the first QNX phone at launch? Not that there are a huge number of apps for BB OS, but clearly based on the PB to date, there are VERY few high quality, useful apps even after 4 or 5 months since launch.