Less of a hassle during purchase experience (prepare to be asked for extended warranty, open BB account, and Geek Squad membership).
Also, if in 3 weeks you decide you'd really rather have a model with different specs, the Apple Store is more likely to let you return your purchase.
That's all I can think of for Apple. On the flip side, if you have a BB card, then you can pay it off over 18 months without interest or get a 5% discount if you plan to pay it off in one billing cycle.
The 18 months no interest thing is probably the biggest differentiator, IMHO.