Had it for 2 days.
User Access Control is the biggest crap ever. You simply cannot designate an older app as "safe" - they all must be signed for that. The POS asks your permission every time you run the program. This is obviously a grab at independent software developers, an attempt to collect a tax from them. I disabled it for now, but this POS is also needed to raise user privileges to admin w/o switching the user, and that is a useful thing. So for now I need to switch to admin user every time I install software.
The speed is OK with 2 GB. The new Aero thingy is really nothing to write home about. The programs I tried so far - my scanner, Adobe Photoshop Elements, Stronghold 2, Firefox, Thunderbird - all work. SH2 in fact works better than on XP.
Overall - greed getting in the way of progress, as is usual with MS.