1: The sprint BB you are referring to is the 8703e I believe?
2. This is indeed a holy war haha. In truth, it all depends on where exactly you use the phone most. I know from experience that Sprint's reception in my primary locations (home, office and the roads in between) was horrid. BUT, they do offer a 30-day risk free period, and if you sign up for their service, realize it doesn't perform in your key areas, you can return the equipment for a full refund, and cancel your contract WITHOUT paying the $200/line early termination fee. Be careful with this, make sure to set your calendars for reminding, and allow an extra 3 days (approx.) if you are porting your number either way (3 days before the 30-day period is over, port it back).
Nobody can really give you a DEFINITE reason to go either way, except you. I didn't find Sprint's customer service particularly pleasing, but then again, I've had the same issues with Verizon's customer service.
Good luck making a hard choice!