I have used the G1 and the G2. It is very easy to use, but I found I needed to develop a habit of checking the distance indication now and again to make sure the camera was close to where I thought it should be focusing.
Could not fault the optics, and generally the speed at which you could pull the camera up and shoot.
I did lose some shots to poor focus, but when I shoot a manual focus camera I sometimes do as well.
Generally found the G2 to be easier, but the G1 is a perfectly usable camera.
Regards, John