I got those two cams for an extensive test and i vastly prefered the Pana. (i use it since 8 months and have so few things to complain about).
Image quality wise, the Pana. was truly better (color fidelity, image definition, etc.) and *much* easier for me to setup properly. The other thing to consider is the true progressive mode (the Canon has just some sort of faked one) . If you work for computer multimedia as i do, this is a no brainer, really. (if you wonder what progressive mode can do, i can send a screen shot to you)
The only reasons why i would go for the Canon would be the more broadcast "look" , lens interchangeability and big camera style shoulder operation. Otherwise, the Pana has a much more manageable size and ergonomics, better image (great optic and recent CCD technology ), real progressive mode, all the advanced user settings you could dream of and a big LCD, so usefull in a day to day basis. It also have excellent mic preamps and general sound features.
Some drawbacks:
- no auto focus in frame mode
- some chroma patterning visible in critical situations
- not enough drag on the focus ring
- no photo capability (who cares anyway!...)
- a noisy motorized zoom