I had a chance to test out the B&O system when I test drove the 2013 7 series. The thing I found with the b&o system was the sound was much crisper and much more detailed than the stock system and I don't know how to explain it but the sound seem to fill the entire cabin much better than the stock system. But the thing that really blew me away was when the sales person played a DVD, the sound was incredible and it was like you were sitting in a very expensive home theater. Unfortunately the thing that turned me off was the option price; the b&o sound system is a $7,000 option which I feel is a bit ridiculous seeing how BMW decided to put such a crappy stock system and than basically tell buyers of a $120k car that if you want a system that actually belongs in a $100k+ luxury car you have to fork over $7,000.
That been said I'm sure a lot people would think spending thousands of dollars on the LED headlamp options or the tech. package makes no sense so I guess it all depends what you want. My advice is go down to a dealership and let your ears do the hearing.