i prefer the index search feature in the start menu in 8. I'm a gmail user, and the same 'find everything and anything by search' ethos is mirrored in the win8 metro start menu. I press the start key on my keyboard, start typing the first few letters of what I want, and 95% of the time it shows up as the first or second option. It's improved even more in win8.1 over 8, as it now searches 'everything' (files, web, programs, control panel) by default, whereas windows 8 would require you to choose the category.
In that sense I don't 'use' metro at all since I'm not finding a tile and clicking on it, but program/file access has been improved IMO.
As has been said, I also find the core to be snappier than win7. The flatter visual aesthetic is nicer, and the upgrades to UI stuff like the task manager, file transfers etc is an improvement. if you're a student, the full version of pro is $70. A steal if you ask me.