What is the difference between those 2 graphics cards?

What is the difference between

AMD Radeon™ HD 6770

Nvidia® GeForce® GTX560Ti

I would want the AMD Radeon™ HD 6770 because it costs less but if the Nvidia® GeForce® GTX560Ti is ALOT better then i will get Geforce

Can you please tell me.|||They are pretty much equal, there are a few differences but I doubt since ur asking this question u would care about them, imo the geforce is better but I'm a nvidia fan, both are good though