Just to add to what Telisha has said above, while Springpad isn’t the most intuitive for task management, the plethora of other functions it offers make it a hugely impressive piece of kit in it’s own right. That too for free.
Personally I use a dedicated task manager for tasks because I need speed of entry for new tasks and calendar integration for the way I work. But I’m definitely considering Springpad for project and reference notes again. I love the fact you can now filter which notebooks you can now see on your screen by category or tag, in theory anyway. Collaboration might not be for everybody but it will certainly be useful for many.
Evernote is a great app in it’s own right but for those who want everything in one place Springpad is still leading from the front IMO. If they could make the task management side a bit more intuitive I’d be more than happy to use it for everything.