Its shit. Plain and simple.
What few improvements it brings (startup times, shutdown times, new task manager...) get undermined by all the stuff that IS NOT included.
The start menu is one thing that sucks, but did you know that the detailed info panel on Win8 is ON THE RIGHT SIDE OF THE SCREEN instead of, you know, at the bottom of the explorer window?
Or how you have to download Minesweeper and Solitaire as APPS from the store and play them in FULLSCREEN?!
You have to jump through a lot of hoops for what would be considered Basic Functionality in Win7, or even XP. The MetroUI is just the tip of the iceberg.
It is NOT Vista all over again. Vista, for all its flaws, had the right ideas, but didn't bother polishing them. Windows 8 stepped up what Vista tried and succeeded with the whole offering, and even a fully patched Vista is a really solid OS these days.
Windows 8 is not, and is heading into a direction that is more than just cancerous for Home PC usage.
This user has been using Win8 for a couple of days, legit Windows 8 Pro Media Center edition. It took him a whole night to get it into basic working condition, which means his everyday use Software and Drivers were installed, the Start Menu and Taskbar Additions were restored and system .dll files edited to workaround some changes to the interface that were simply obnoxious to deal with.
He's seen the beast and warns you out of personal experience to stick close to your guns - aka Windows 7.