The taskbar is one thing, but it's horribly slow, even on a rather high spec laptop. The delay from clicking start menu icons to programs starting is very noticeable, and some programs freeze regularly. MS Office are actually some of the worst offenders. I tried it for 2 weeks and then did a fresh install of Windows 10.
I didn't even mind ME, for me it was running pretty stable. I heard most issues came from people updating from 98 or 98SE to ME, a clean install was usually stable.
I skipped Vista though, went straight to 7. Still my favorite Windows. 8 was crap, 8.1 was not bad once you applied the taskbar fix.