I've ranted about the dumbing down of UIs previously on HN (re: Windows 8 Metro/WinRT, OS X Launchpad), but none are as terrible as Unity. It's impossible to find what you're looking for with it, it's terribly unintuitive, it hinders productivity more than any of the other offerings, makes it impossible to find out what applications you have (since software store apps and normal apps are held separate), and once Gnome fallback is disabled/no longer ships, will be shoved down users' throats more than WinRT or Launchpad are.
This and a number of other missteps on Canonical's side (cough Amazon cough) have made me a disbeliever.
I've actually spoken at length with some Canonical business representatives out of London on this issue, and when I laid out some of the limitations of Unity to them over the phone, I was surprised to hear them readily agree that it's nowhere near perfect, and in many ways a step back from the tried and tested UX. I can't remember the specific complaints that I voiced at the time (this was a while ago), but they promised to be in touch when the issues have been addressed, but I'm not holding my breath on that happening.