I am using 8
It's ok, I guess,
multi monitor support is nicer something I would like to have seen on earlier versions
storage stuff is a lot better and it mounts ISO's natively with drive letters and everything.
windows key and typing is ok, like 7 but it is too invasive, I might not want/need a whole screen to switch when searching for an app, if I am videoconferencing I might need to launch something ( not on my taskbar or in the formerly start menu start bar - I do not like having a cluttered taskbar so nothing is pinned there - the start menu was great for pinned stuff to launch, and less overall movement of the mouse if you have a screen full of icons)
the whole shutdown thing is not good, nor is getting to system settings and such, very unintuitive, the menues up the sides (which is also a tad annoying on multi monitors since it is on the sides of all monitors not just the far left/right sides) I ended up making a command prompt shortcut for faster reboots ( another darn icon) i know i do not have to reboot all the time i have not rebooted in over a week so far, but when i do i want it to be simple ( I know intuitive - go to START and select SHUTDOWN :-/ probably why it was called the windows button later not start)
i do have a lot more icons than I used to on the desktop, just quicker than windows key + typing, i fast high res mouse speeds across the screen with ease and it is often more muscle memory then observance will take a bit more getting used to with 8.
ctrl+scroll wheel zooms the app windows both tiles and all apps, useful, sort of not used much
the big thing is more keyboard use, before there may have been a time when i never needed to touch a keyboard (and vice versa with the mouse) but now it seems a lot harder to do - quickly, I do find searching through the all apps screen more difficult then the start menu, i am sure with use it will come easier, however this leads to my biggest issue:
The company i work with are going to deploy 8, we already have it and a using it, a lot of the people in my dept use 3rd party for start menu, which to me defeats the purpose, of the out of box experience, namely i should not have to install a 3rd party app to give me oem functionality even though it was the oem that changed it.
I have gotten used to 8, nearly, the 500 plus employees however is going to be a nightmare, vista was a nightmare, 7 they sort of took too, 8 is a radical change, and while adaptation is possible i feel it will result initiall in lost productivity, and, if Microsoft change the ui back or more in a future release, it will result in more frustration, remember this is not all "professional IT people" using this many people are only comfortable enough with a computer for work, some set things up in a specific way for their workflow, they will have to totally reorganize themselves when this is deployed, a situation that is frustrating for them, and us since we will have to spend out time helping them get back to at least a partial level of functionality they are used to.
yes things change, however there should simply have been an option for the "legacy" start application get people used to the new UI without ramming it on them and giving no option (and no buying the 3rd party app for every user is silly and should not have needed to be an option)
My wife, who was in level 1 support for a cable company, already has had numerous confused callers who got new pc's with 8 on them and cannot do the most basic things, even her support team were slow at helping since they had to find out how to do it too something that took 3 minutes in 7 now takes 5 plus in 8 with a lot more clicking and keyboarding, which is frustrating to none power users.
That is my biggest gripe, ok if you are new to windows/computers like say a young kid great! i think 8 will be good for them and they will do awesome ( and equally be frustrated with the "legacy" interfaces, however we are not all new to computers, and relearning how to walk again can really take the wind out of your sails, not to mention waste time for all the IT staff trying to help the users do their jobs!
for the moment I am not recommending 8 to anyone who is not overly familiar with using them, for new users I do and for IT people, whatever, you are in IT stuff changes quicker than the postman hearing the husbands key in the front door. (however change is still frustrating and the change to 8 has made my job less satisfying for now).