It's pretty much required to keep CUA hotkeys in your head in some form. So I find switching between Emacs/Eclipse tolerable and kind of necessary if I'm doing

It's pretty much required to keep CUA hotkeys in your head in some form. So I find switching between Emacs/Eclipse tolerable and kind of necessary if I'm doing Java. I think switching between Emacs and Vim is a good idea but more a question of keeping your hand/mind coordination flexible for different input paradigms. I'd be skeptical that they're really that different in terms of efficiency for a task, but I'd say learning both really well will make you more efficient in general.