There is general mapping software available for the Blackberry, with ability to take a GPS input, but it is not designed for aviation nor does it support the UK Blackberry models.
http://blackberry.1map.info/ The small screen of a Blackberry is going to make for a fairly poor map display.
On the question of Bluetooth, I've never had any problems (no dropped connections, no interference) using it in the cockpit, though that is not to say someone else won't or that I never will.
KCDW your conclusions seem about right, which is why despite having tried these various options I mostly use a Garmin 196, occasionally supplemented with a MemoryMap CAA chart. In the US I have used AnywhereMap and it is excellent.