The GH1 offers plenty of manual and semi-manual features to please amateurs and enthusiasts, but you can run on full or semi-automatic if all the buttons and dials scare you. Several features stand out from the crowd, though.
The 67mm (3 inches), 460,000-pixel flip-and-twist LCD is a big attraction. It's a good LCD, but keep in mind that because it's a wide-aspect LCD, it crops standard-aspect photos with vertical black bands so they don't display as large as on typical LCDs. It's like displaying 4:3 or 3:2 photos on a 64mm (2.5 inches) LCD.
There's also a mode that you can preview changes to settings such as aperture and shutter speed to gauge the effects in advance. Though it's somewhat hard to see depth-of-field changes, and you can only get a general sense of the shutter speed affect because of the LCD refresh, the capability to preview exposure may be invaluable for some.
Unfortunately, this only works in Program mode, rather than modes where you have independent control over those parameters. You can also save three sets of custom settings. While we'd rather be able to access them directly from the mode dial instead of just the single Cust slot with menu flipping to select one, this is much better than nothing. In addition to traditional exposure and white-balance bracketing, you can bracket three different film modes.
The GH1's EVF is pretty good. It's bright and easy to see, with good scene coverage and a relatively speedy refresh in bright light. In dim light, like all EVFs, the refresh rate slows dramatically. On the upside, you can shoot video while holding the camera up to your eye, unlike the SLR experience.
For some reason, Panasonic doesn't let you disable auto review while burst shooting. You're stuck watching what happened rather than tracking what's going to happen, making it very frustrating to shoot action photos.
While it's a little slower than typical good dSLRs -- including less-expensive models like the Canon EOS 500d and Nikon D5000 -- the GH1 performs quite well. The autofocus system operates quickly, especially compared with the Live Mode AF of digital SLRs. It supports continuous AF during movie capture and is pretty responsive.
It powers up and shoots more slowly than the G1, but that 1.8 seconds is still sufficiently fast. In bright light, the camera snaps a photo in 0.4 seconds; in low-contrast light, it takes 0.6 seconds. It typically takes about 0.9 seconds to shoot two consecutive images, with barely a second added for flash recycling time.