Originally Posted by JetSpeed
I had the same problem with my Nav-IV and was eager to replace it with the Nav-V knowing that if it exhibited the same problems I would quickly return it for a refund.
I've had the Nav-V since introduction with nearly 4k miles on it and have not had any MP3 or BT issues, it is a joy to use in comparison to the Nav-IV which was a waste of money.
My only small gripe wit hthe V is that even though the screen is much improved I still wish that it was brighter, although it is very usable and nice for the most part.
Have you experimented with the different map "themes"? Although they do not change the screen brightness, I find that some are easier for my aging eyes to see than others. Currently using "Ostereich".