NVU developer Daniel Glazman posted a lengthy review of Internet Explorer 7 with tons of screenshots and thoughts on the UI. His views mirror a lot of those from others I've read on the blogosphere. I found Internet Explorer 7 pretty bad and hard to use when I tried it and I'm actually quite unsure whether this is an upgrade or a "downgrade". UI certainly needs lots of tidy up.
I don't know how I could ever go back to using Internet Explorer. Glazman concludes: "Overall, and if I compare Firefox 1.0 or Firefox 1.5 and IE7b2, Firefox is far ahead of IE in terms of usability, accessibility, extensibility."
He's done what most of the famed bloggers have done, which is to review it install on XP SP2. IE7 isn't designed to fit nicely with XP SP2 and the fucked interface shows that nicely.
IE7 really does improve once you run it on Vista, which shares the same odd UI configuration.