Developing on the BlackBerry 10 OS has actually been a pleasant experience, but that was for fun rather than profit, as the numbers do not add up in their store vs the rest of the market. Their android runtime is very good and most apps run well on it, with the confidence of a modicum more sandboxing than a native android phone. I think BlackBerry's only real hope now is to get the phone into the hands of people for little to no cost and hold developer events and contests. It will cost them to have a dev community, like Microsoft learnt, but without it, they will wither even more so.