Daft

I haven’t kept up with Canon news, but I looked into it, and the 600D is simply the 550D’s successor, the new model in Canon’s entry level DSLR series. It has the same sensor and image processor, so image quality is the same. If you like the few new features the 600D provides, like the swivel screen, then go for it.

Not being someone with hands-on experience, I don’t know anything about custom firmwares, if you want to experiment with those, well, it’s your risk to take .