DSLR Buying Suggestion Needed

I currently have Nikon D3100 with kit lens and I am selling it next week to move to Canon mainly because of better video features. I actually planned to get 600D with 50mm f/1.8. I read a bit about 650D and it looks way better with new image processor and continuous focus thingy. Now the question is that is 650D worth spending over 600D?

And can anyone please explain focus system of 600D in video mode?

Regards.