I've owned both. My flying brick was a K100RT. Rode it a lot for 7 years. I've put 18,000 miles on the Valk in the last three years.
BMWs are sportier. They are FAR more maintenance intensive, although if you do the maintenance, they will last forever. If you don't they are troublesome.
With the Honda, you can ignore it and it'll still last forever.
My Valk will spank the dog**** out of the Bimmer in just about every aspect, except MAYBE a really twisty road. There it would be close enough to depend on the rider's skill.
The Honda is faster, smoother, way more reliable, and better looking. The BMW has an annoying whine all of the time and a annoying vibration right at cruising speed. The Valk has a lot of transmission whine that can be cured by synthetic oil and better than stock pipes. It has perfect balance at all speeds. You can balance a nickel on it's edge on the valve cover from start up to red line.
Both have very defined riding position. The wide low motors don't give much in the way of foot forward riding position. You can get Kuryakin pegs for the Valk that work well, and taller seats if you're tall. In fact, the Venture seat on the purple bike above is about the best aftermarket seat you can get. It's high on my priority list. The forward part of the seat is wide. That makes shorter riders have a tough time holding 800# of bike up. The Bimmer is also pretty tall. The fairing design really gives you very limited movement, but you can still do a lot of miles on the K-whiner.
If that's a picture of you in your avatar, you want to test ride the BMW. I got mine from a larger gentleman who found it very uncomfortable. I don't know how well I'd fit myself anymore. They are really best for folks in a certain height and weight range.
Parts and service for the Honda are also considerably cheaper.
97 was the first year for the Valk. They had wheel bearing issues and seats that would put your nuts to sleep. They also had the highest hp rating of any year. 100+, IIRC. You might want to do some research on it first.
http://www.valkyrieriders.com/
Anything else you have a question about I'd be happy to give you my informed (for once) opinion.
