I installed it on a spare partition, with dual-boot Win7 or Win8.
I think it was designed for a touch-screen (iPad-like). Finding the "start" button is a faff, whereas I suspect swiping might work. I don't have a touch-screen monitor so can't try that.
It didn't seem any faster than Win 7. I set up Thunderbird and Firefox, pointing at the same "Mail" partition Win 7 uses, and it seemed quite able to handle that.
After a few hours tinkering, without installing MS Office or any other added software, I couldn't see anything it does better than Win 7. I didn't check all the peripherals for drivers/function, but the ones I tried worked OK.
When I was running the Win 7 pre-release versions, I soon stopped using XP and switched to Win 7. I can't see me doing that with Win 8.
When I switched back from 8 to 7 last night, all the hard drives/partitions were marked "dirty" and I had to wait for chkdsk to work through them all.