I love my Q10 and I truly hope Blackberry recovers in the future, but you're right - it does look like a dead end OS. There are a lot of apps that you'll find simply aren't there; I don't really use that many apps, but there is almost always something that I am wishing it had (like a decent Roku remote app). BB10 is a nice OS though and the phone runs smooth; it sort-of supports android apps (that don't require google services), but the experience is lacking.
In the end, as much as I LOVE having a physical keyboard, I have a Nexus 6 arriving - probably - next week (they were 300$ new on eBay).
Edit: To touch more on the Priv - BB makes quality hardware, so I wouldn't hesitate in that regard. I hate the form factor of the Priv however and it will be their first experience with a full android OS. That, plus what will presumably be a high cost (or higher than I paid for the Nexus), would have me looking at other phones unless I NEEDED that physical keyboard.