There's nothing wrong with the 560, it's been out for years. I'm on several Bernina yahoo groups and other forums, and i never heard a single complaint about the 560. I wouldn't hesitate to buy one, even online. Now that it has been discontinued, it's available online, for as low as $2399.
I'm a big fan of the 5.5mm stitch width, so I just bought an "old" Bernina 570 QE with the CB hook, similar to the 560, except that the 560 has a rotary hook and 9mm stitch width.
The 7 series have a new hook system, the Bernina hook system. Dealers are raving about it. People I know have had mixed experiences with the 7s. I'd have to test drive one extensively before I'd buy. Since I have an 820 with the big harp, jumbo bobbin, dual feed, and the 9mm width, I haven't tried the 7 series.
Just try them both and decide based on your test drive. Good luck!