I tried both the AE8000 and 5020UB. I found the lens shift controls on the Epson to be terrible. The dial action had a ton of slack before actually starting to move the picture, and one dial would drag the other unless you held it in place. Basically you can't legitimately call one horizontal and the other vertical, because one doesn't stay in place while you're adjusting the other. It's possible I had a bad unit, but I much preferred the Panny's lockable joystick.
I don't find any significant image quality problems induced by using lens shift, but then again, my projector is pretty near the center of the screen to begin with so I'm not using much.