Do you think as an OS it is workable on a multi-monitor setup? In particular with either the left or right hand "hot corners" (hot edges? hot sides?) being unreliable?
Also how much time do you spend in Metro Vs. the "desktop?"
It's 100% workable on multi-mon, *especially* with the hot corners in the RP - they're pretty reliable on my rig. Because of how my monitors are oriented, the hot corners aren't as relevant though - my monitors are oriented like this: ||= so the hot corners are only active on the right monitor at the top left and bottom right - the middle corners on the left monitor already have infinite fitts distance because the mouse gets "trapped" in the corners.
I spend about 95% of my time in the desktop environment, that's because the primary tools I use are almost all desktop apps (my day job is building code for Windows and the command interpreter is a desktop app). I use the metro email app for my personal email pretty much exclusively, and the metro calendar for my personal calendar (I merged my work calendar into it earlier today actually). I use the music app all the time to listen to my music collection, but since the music plays in the background, it doesn't really count as being in "metro".
I also spend some time each day playing some of the various metro games in the RP, some of them are pretty good, some are just ok. That's expected with any platform.