I installed W8CP on a spare 1TB HDD. Have been using it for about a week. Here are my thoughts/stories:
1) I like the metro design. Everything is all in one spot. I like the built-in apps. Weather, Finance, etc are all very well done and can be easily customized to my desire. I like having a "one-stop-shop" for everything.
2) I am running eyefinity and W8CP is really lacking in this regard. Metro runs on my center monitor. I open programs in Metro and I can't drag them to the other monitors. Whatever I open in Metro stays on my center monitor. Very disappointing, limiting, as one of the main benefits of eyefinity is the easy multi-tasking/many windows open. I want to use Metro for everything but simply cannot because of this.
3) I had W8CP up when my girlfriend and Mom came over. Didn't tell either of them anything about it. Girlfriend: looked at center screen, didn't do anything. Looked at my other two monitors (with desktop) and clicked the internet explorer icon on the desktop monitor, rather than on the metro GUI. I thought that was interesting. Mom: immediately keyed in on the "people" tile on the metro GUI. This was putting live updates from my facebook account, and she clicked on it immediately to see what my cousins and everyone else were up to. Interesting.
4) I feel the Metro GUI will simplify the computing experience for those that need it, 90% of the users. It's meant to do all the work for you, put everything in one spot. It's like if you're too stupid to set up a mail program, organize your photos, and browse to facebook, we'll do all of it for you. Since I (and probably everyone here) have no problem setting these items ourselves, we prefer W7 desktop, as it's more powerful and has less limitations. I wouldn't imagine many power users will uprgade but it is a simplified/fun version for most computing users.
5) I do hope they improve the interface with keyboard/mouse. Some things aren't very intuitive.
Edit: W7 drivers for my AuzenTech X-Plosion sound card did not work with W8. Might just be a problem with the installer though, as the installer said, "this system not supported."