I played through all the free levels. It's slow, you don't learn a lot, and you end up having to pay to keep going.

If you are learning I'd advise you to check stuff like this: http://www.viemu.com/a_vi_vim_graphical_cheat_sheet_tutorial...

They show you a few shortcuts on a keyboard layout and they keep on adding shortcuts to the pictures so you can learn at a nice pace.