I've got one that I built up (so i could do it with campy). I can't really compare it to much as I am a youngin' whose only ridden a couple different tri bikes.
It seems a little lighter and better handling than some of the others I have tried. Carbon seat stays are also a plus if you plan on using it for longer rides. My decision to choose that bike mostly came down to the fit. 56 fits me quite nicely.
I don't really think it's that great of a deal. A cervelo P3 Carbon w/ dura-ace is pretty close to the same price and may be a little more bang for the buck.
With that being said, I've been very happy with mine so far and am looking forward to putting lots more miles on it next year.
I own a Felt S25 which has the same geometry as the B2 but without the carbon stays. Felt tends to be a good fit for people who have propotionately longer torso/shorter legs because of the long top tube. I have short legs, so the Felt is a really good match for me.
If you have fairly long legs for your height, I'd agree with nnewton123 - check out the Cervelo P3 carbon. Also, Cervelo just released the P2 carbon which has the same components specifications as the P3 carbon but is priced at $3,600. Since it's new, availability may be a problem.
By the way, in the 2005 Kona Ironman, Cervelo was the most popular bike brand. They make some really nice bikes.