When looking earlier this year, I auditioned the 804s, 805s, and Linn 5140s. Found that the Linns had more, smoother bass than the 804s and 805s. Agree that 804s didn't seem worth the extra money, but I do have a friend who has them & swears by them. I also agree that the B&Ws in general might provide a little more clarity than the 5140s (which are very smooth compared to the slightly harsh lower-end Ninkas).
At the end of the day, I got the store demo set of the 5140s because I didn't want to shell out the extra $1000 for the 804s and didn't like the lack of bass in the 805s. Also, I like the fact that the Linns could be placed pretty close to the wall -- I live in NYC. I felt I would have had to spend a lot more to do better than the 5140s or 804s. I'm very happy with my purchase. The same friend, who heard the 5140s with my very modest power behind them recently, thought again about his B&W stuff -- he figured he could have saved himself the extra money for the 804s *and* the B&W woofer he bought to boost their bass by going Linn. When he gets home to Seattle, though, he listens to the greater clarity of the B&Ws and changes his mind. It's only money, right? You can't go wrong. Good luck.