We said the same of the G1, but it bears repeating: Panasonic has hit on a good combination that makes us appreciate the original mission of Four Thirds, which was to produce smaller cameras and smaller optics while achieving higher optical quality.
If you’re looking for high-definition video in a DSLR format, then the Panasonic GH1 is easily your best choice. The ability to continuously auto-focus during recording simply isn’t offered by the likes of the Canon EOS 500D or Nikon D5000, which force the user to manually focus.
If you’re looking for a compact, interchangeable lens camera that can record movies in Full HD, then then Panasonic DMC-GH1 is the only game in town (yes, the Canon EOS-5D Mark II can do it too, but it’s not in the same class).
If you’re willing to pay a premium to be on the cutting edge of digital photography and video, and as long as you don’t shoot sports or in dark venues, then you’ll likely love the Panasonic Lumix DMC-GH1.