Do they actually work for coder-style usage? Would I actually be faster in Emacs if I was constantly looking to see what my keyboard had been redefined to this time?

Intellisense/autocomplete in Eclipse and Vim is the one are of desktop computing where I do get assistance, and it works great. It's not autocorrect, but it's two characters and then tab of crtl-space or whatever and tab or arrow key to the word of my choice.