I've just downloaded and installed the latest beta version of Vista, build 5365. The installation was relatively uneventful and in use, VIsta seems relatively smooth. The new pictures and screen savers are very cool to look at. With my big screen (24" wide screen TFT) and a reasonable graphics card (GeForce FX 5200) Vista looks very nice with all the eye candy. But it's still a beta.
But from a usability point of view, 5365 still seems to suffer from a "let's move stuff around because we can" syndrome. Sadly things that were easy to find in XP have been moved around for no obvious reason. Although I do like some of the improvements, the consistent sense of inconsistency in XP continues - we just have different bits that are inconsistent.
There are some other things about 5365 I hate - particularly UAP. The concept of forcing users to run with relatively low privaleges is a great one. But the implementation is Vista is just plain lame. As I'm setting up the system, the entire screen goes black for 2-3 seconds (a visual sensation similar to what we saw when XP blue-screened) then a silly dialog box pops up - I click Accept - the screen goes black for another 2-3 seconds, and I can carry on. It's very, very annoying - sufficiently so that I'm going to just log on with admin privaleges. It's easier and far less intrusive. Sadly, while I like the concept, MS has made a poor job of the implementation. Of course, mileage may vary on this - but I doubt many IT Pros will even come close to liking this implementation. We'll see.