Well you asked on the Panasonic forum... but here goes with a few of the advantages each has to offer.
HVX200
DVCPROHD codec at full 100 Mbit
Lower price.
Couple of years head start on tapeless workflow and 3rd party equipment market.
More crews experienced working with it.
4 channels of audio
EX1
More footage on a card (though as a long gop format).
1920x1080 imager on 1/2" chips- means shallower depth of field.
SxS cards fit in MacBook Pros with ExpressCard Slot.
HD-SDI out.
The bottom line is that these are both formidable cameras and you would do well to get a demo of both to see which you personally prefer.
-Noah
My FCP Blog. Unlock the secrets of the DVX100, HVX200 and Apple Color. Now featuring the
Sony EX1 Guidebook
http://www.callboxlive.com