I've never seen a store boost coverage. I've seen some pretty bad coverage at stores actually. So it's real. You just don't know how far out it extends beyond the store area right now.
The HSPA+ is pretty darn fast too. Plus the whole talking + surfing at the same time thing (which is important for me in the car, getting TomTom traffic updates while talking on the bluetooth). I'd have a hard time finding a reason to switch to VZN right now.