FP 2003 since the first beta, and I'm very happy with it. As far as I'm concerned it's the best version so far, and the final release should be worth waiting for.
Don't get too hung up on this FP extensions thing - most ISPs will support them, and if yours doesn't you can always ask them to install the extensions. They're free to download, and don't take much time to install and configure on a server.
The extensions are required to run some of the enhanced FP components like hover buttons, animated text effects and forms, but it's quite possible to design and upload a very good site in FrontPage without these components, and without the extensions being on the server.