I tried win8RP and CP, and they were OK, then when I got RTM I was finally happy with the improvements they made and I have been running it since Aug 1st when it became available. It is not perfect, but most definitely faster than win7. I spend most of my time in the desktop mode though, and rarely have to ever see the start screen except when I want to use a metro app.
I purchased a copy of win8 for my touch screen netbook because win8 is sweet on a touch screen, but am waiting to see how WP8 is before I purchase for everything else. $40 is a great price, but it gets pricey when you need 4 copies to get everything updated. To me it is worth it if everything is going to be running a similar interface... not so worth it if I end up going with an android phone.
BTW: Microcenter has the disc copy (both 32 and 64bit in 1 box) for $40 instead of the $70 that everyone else has it for. It is fine to DL it and burn it to a disc or flash drive, but for the same price you may as well grab a physical copy.