I haven't played around with the Sony, but a friend has the Lumix GF1...it's really nice. easy controls, nice back LCD panel and takes nice photos.
What I've learned in this category of camera, is they all take great pictures, have about the same lenses and access. etc. I think it comes down to post sale support, ease of use/how intuitive you feel the camera is to use.
BTW, this is a really cool camera technology.