Huw Collingbourne of Bitwise magazine has written a very good review of BDS 2006. Bitwise has also published a review of BDS2006 written by a Visual Studio guy, Dermont Hogan. While he wasn't conviced to switch tools, I found this thoughtful review to be well considered and balanced. Thanks, Huw and Dermot!
Update: Speaking of reviews... This one is a little confusing.