You didn't say whether 3D is a requirement. Sharp still use active 3D. Therefore I'd get the 650 (non-3D) if I were you.
I faced a similar choice when I decided to get a 70" Sharp, and got the 640 (non-3D) model. Mind you, I also have an LG 65LW6500 (passive 3D) TV. Anyway, my Sharp has a pretty good picture for the money, once it was dialed in. The presets are unimpressive, to say the least. So look at the dedicated thread for whatever you get, and try some of the calibration settings posted there.