I can't say what's right for you, but if I get a new machine it will be the 770 - I actually saved up for it for a couple years, just haven't pulled the trigger. The throat space is a big, big deal. Having the BSR is great, but if you can't easily move the quilt around you won't like free motion.
If I were you, I would take a lap quilt in and ask to try the 560. See if you can FMQ the middle of the quilt without trouble. If the throat is too small, you will know right away. This will also give you a chance to try the two different BSR modes, and see which you like.
My dealer let me play with the 770 for over an hour, trying different threads etc, to see if I really wanted it. I'm in love with the BSR, but I need the throat space to go with it. Hopefully your dealer will have floor models for you to try.