I was in the same boat as you a few months ago and couldn't decide what one to get, I picked the 600D
It has a built in user guide-good for me as a i had no idea what half the buttons do and mean
It see's colour do shots are always great with great intensity
Flees great in my hands
Lots of parts are upgradable to make it even better!
Nikon cameras I didn't get on with at the shop so there out the question straight away for me
There's loads more useful stuff the 600D does but I dont know any of it