I just got my Z2 last week, and couldn't be more pleased with it. I seriously considered the Panny 500, but chose the Sanyo over it's greater versatility in position relative to the screen through it's horizontal and vertical lens shift. I'm in the military and need to move frequently, so that extra leeway in positioning the unit is nice insurance for the future.
Based on the shootout at PJCentral, you can't really go wrong with either one at that price point.