One thing I like about G1 is that when you fully press the shutter and if there is a shutter release lag and when you decided not to capture the shot and when you release the shutter, the G1 will not fire the shutter. In most compact digicams and phone cameras, the shutter will continue to fire even after you release the shutter. That's very annoying because it deprives the user of re-framing the next shot.
The G1 is generous with hardware switches, like auto-focus dial, burst mode selector. Controls are generally easy to grasp. THe 3-inch articulated LCD monitor is a plus point that improves versatility. The start-up is extremely fast compared to most compact digicams: I can take the shot within 1 second of switching on (providing AF is locked). The LCD monitor is very clear and sharp. In fact, the live view looks better than the shot image.
Like many new Lumix models, the G1 comes with a special AF-lock that literally locks any item within the frame and tracks it anywhere it goes. This is really helpful when you want to shoot a moving object, and it tracks really fast. The first time I tried this "3D-tracking" feature was on my Nikon D300 DSLR, and now that I've tried on the G1, I realised the D300 tracking was considered slow. But in all fairness, it cannot be compared, because DSLRs uses fixed-location sensors across the frame while compact cameras use virtual sensors on any area on a frame.
The only thing G1 doesn't do like a normal compact digicam is to record video.
The review set I was holding comes with the 14-45mm (equiv. 28-90mm) f3.5-5.6 lens. The small-aperture lens did not help to demonstrate the advantages of G1. At the indoors, I wasn't able to capture still shots of active Mayenne despite bumping the ISO to 3200. However, shots that got her are sharp and clean. I believe the G1 will shine once better lenses are fitted.
While the G1 performs better at outdoors, focusing speed is not as reliable. There was a shot where I totally missed despite trying to refocus twice. The shutter refused to release because focus was not established. In majority cases though, focus is fast and snappy.
The Lumix G1 is a showcase of technological advances and will help in future product releases. On one hand, compact digicams could perform faster and produce cleaner images. On the other hand, DSLRs will become smaller and more compact.
If you need a compact digicam with superb handling speed and good image noise control, then G1 has no competition. If you prefer an analogue photo-capturing experience without the digitised live view, then nothing beats a real DSLR.