I've been using it for about a month now and haven't had any problems. The install was quick and painless, the only hardware drivers it didn't install automatically were for my HP printer and my ASUS on-board audio. It found the printer driver fast enough off the HP cd and I solved the audio problem w/some determined googling. It took 2 secs to setup my dual-monitors the way I wanted them.
As for UAC, which has caused so much brouhaha, it takes about 4 clicks to disable it and forget about it forever.
All my commercial and freeware programs seem to be working just fine, including MetaStock 7.2 Pro.
Vista is blazing fast on my system, w/o a doubt faster than XP. Even my internet surfing is faster. I also love the look and the way the windows kind of fade in and out, it's so smooth. And the semi-transparent windows are just too cool for school. Eye candy? Yes, but I like eye candy. Sue me. Vista looks great.
Harold