Longest post title ever.
I’m currently trying out OSX 10.9. I’m coming from 10.6.8 and one of the many annoying little things is that Ctrl-left/right arrow is now used to jump between Spaces/fullscreen apps (which I don’t use) and therefore you can’t use it to jump to the beginning or end of a line of text (in a text editor, e-mail, Firefox bar) anymore. I actually tried to get accustomed to the other shortcut you can use to jump to the beginning and end of a line Ctrl-a/e but that is not really a shortcut that works that well.
But: you can turn off the switching of Spaces with Ctrl-arrow keys in System Preferences > Keyboard > Shortcuts > Mission Control (these are on-the-fly translations from a German OS) and tadaaa: welcome back old shortcut.
Another little annoyance gone. There isn’t anything in 10.9 that I like better then 10.6.8, though. If it turns out that battery life really is longer I might stay with 10.9.
P.S.: Another little thing: three finger-swipe to go back and forth between websites in Firefox (and Safari?) turned into two finger-swipe.