I don't know about the grits but my 800+ has the auto drive and case feeder and I can load a box a shells so fast it will make your head swim. Not bragging but in my eyes my setup is as good as it gets.
I agree on the joystick control. It will keep your right hand out of the linkeage. You can back up instantly with the joystick. This lets you straighten a folded wad petal. To back up with the foot pedal you must change a switch on the black box and then press the foot pedal again.
I had mine on a 900 for about a year. Just bought a 800 Plus and put the Auto-Drive on it. It is THE way to go!