I boot Ubuntu almost everyday, and I still happen to position my mouse at the bottom when I want to access the application bar, before realising that nothing comes up and I went in the wrong place.
It's funny how the screen setup has become just like a reflex after years and years of practice. It's really hard to get used to new choices in design.
I have never really been a user of Ubuntu myself but when I (mainly) switched to Linux from Windows, it only took a couple of day to get used to it. Then again, I was never clicking the icons in the application bar before (win key -> typing -> enter).
Seriously -- If you have a normal laptop / modern screen -- it's time to switch. It will take some time to adjust -- but it's worth it for the vertical space you reclaim.