I have both, but IMO its easier to use Springpad to create a task quickly. If you're using a GTD system (which is what I'm trying out for both Springpad and Evernote), try Remember The Milk!
Springpad for me. The various catagories available to create and sort everything into far exceeds that of Evernote. The interface is cleaner and the options are better. (all personal opinion, of course)