Expression Web went final back in November. I tried it on my test box. It is a huge improvement over FrontPage but it still has some catching up to do against Dreamweaver. It is a very good first attempt for a complete overhaul.
I may give it a shot as Frontpage has been my product of choice for awhile. I know Frontpage is relatively dead as of now, and the features within have been suitable enough that I haven't needed to transition to Dreamweaver.