Here are some updates on my experience using Windows 8 Release Preview, Evaluation copy build 8400, now that it's been a little while. You can download, install, and use the same build for free courtesy of MS (google it).
I still like it better than 7, although I have had it freeze on me once (7 never did this). If it does so again I will swap back to my 7 ssd most likely until it's ready for prime-time.
I noticed that if you swipe in from the very left or right edge of the touchpad, it opens the tile/metro-styled app manager or the charms bar, respectively, in a similar fashion to mobile OSes (think dragging down notification bar from the top with Android).
This is the charms bar, in case you don't know:
I tried plugging in a foreign (not previously installed) printer, and it installed without any notifications and was immediately available for printing.
I also hooked up my bluetooth earphones (Motorola S305s, which cost ~$25) pretty much instantaneously. (Aside: for other cool gadgets I carry with me, check out this post).
Being a heavy user of the start button to initiate a gnome-do//spotlight search for programs and files, I do find it somewhat annoying that instead of a small bar on the left I am forced to see the metro-style search view. However, after a little while I started getting used to it and the benefit of a larger search results screen has started to outweigh the original aesthetic nuisance.
The main thing I'm excited about is the full-circle cloud integration to enable a ChromeOS-esque consistency of data AND settings. Take a look at this page: