I'm going to wait a day or 2... my 2007 MacBook won't be able to use but 2 of the 5 big improvements.. my wife's 2008 iMac 3 of them. Still going to do it but not ina rush.
I'm on it now. Upon restarting after install, it took a few to finally get the desktop, then I was getting spinning beachballs on some stuff. I think it was just sorting things out because now it works fine.
i upgraded my Macbook and i'll do my Mac Pro later (along with my wife and son's computers). the install took me about an hour, i'd guess. but it's humming right along.
it doesn't tell you how much hard disk space you get back, so i'll probably make note of what i have before the install on the other machines just out of curiosity.