I've been using the Windows 7 beta for a little over a week now. I can honestly say it is not bad. It doesn't feel like a completely new OS by any long shot, but the subtle improvements over vista make it so much better. No weird quirks, manages resources better (you no longer have to wait 5 minutes after log on to do anything because superfetch is thrashing your HD) Over all GUI transitions and effects are smoother and more polished as well. Fresh install also seems to take up less space. But that may change in the retail versions with more stuff installed.
Annoyances:
UAC, while it is tuned down in 7, it is still annoying when working with potentially protected files on another harddrive (like on my XP install), it asks you for permission to access virtually any file, and I can't find any option along the lines of "Do this action for every file".
Any of the Windows Live (sort of similar to Add&Remove programs in ubunutu, but way more limited) "add ons", such as moviemaker automatically install Live Messenger, and if you select to not to install messenger
The Control panel now has two modes. Crippled and Ridiculously unintuitive. Heres' two pictures showing what i mean
http://hosting03.imagecross.com/image-hosting-08/5476Untitled1.pnghttp://hosting03.imagecross.com/image-hosting-08/7025Untitled.pngInteresting Bits:
They finally updated paint, to make it match the "Ribbon" interface of their other newer products, such as Office 2007, and added many features that it SHOULD of had years ago. Also, PNG is the default save format, and the compression does not seem to bad at all
http://i44.tinypic.com/2ut1f9g.pngThe taskbar has been updated. Programs now get put into their own "square", and you mouse over to see the open windows of that program or folder. (Little image preview). You can also place shortcuts/folders/executeables into the taskbar as quicklaunches, and when clicked upon, the window gets grouped into that quick launch button. If you mouse over one of the little preview images, it makes every window disappear but that one.
Picture demonstrating it. The IE, Folder Icon and the "Play/Windows Media" button are also quick launches.
http://i44.tinypic.com/33my521.png (The outline you see is an open folder that went invisible)(Also the media controls on the preview should be noted)
I do kind of like the setup, however the biggest annoyance I have with it is that it does not tell you how many windows/instances there are with a little number, in say the corner of the box. Sometimes during normal browsing, I may end up with 4,5,6 instances of Firefox, and I don't even find out until I mouse over the firefox icon.