Once you get used to it, the new Start menu is ok. You don't spend much time in there anyway.
The real pain in the ass are the stupid full screen Metro apps. Yeah, they just pop up with brightly colored interface that is optimized for touch. They completely disrupt your workflow, there is no visible Exit-button, and they do that for one screen only (if you have multimonitor system, you will totally hate this).
This happens more every now and then and I have to go through some trouble to replace them with better OSS alternatives. If you are watching a video, default app might pop up, and maybe nag about codec or not being up to date - when you really just want to see the video now, with clear controls. PDF reader pops up with no clear navigation and ofcourse fullscreen, and these ofcourse always go to the same monitor, even if you would like to read the PDF on screen #2, while coding. Shit like this happens also with images and music, and the interface is just .. horrible.
I don't even care anymore, if they fixed this. I've been downloading OSS replacements for just about every program and I am curretly ok with my Windows. But instead of fixing the Start menu, which is only a minor nuisance, they could make WINDOWED and USABLE default apps.
They should also shoot the guy, who designed all their new software (Office, Visual Studio..) USING ONLY CAPS FOR TITLES, patch them back to normal and make my eyes hurt less.