Having owned Panasonic Lumix, Leica Dlux4, Canon G11 and Olympus PEN EP1 cameras, I am also waiting hopefully for the X1. The PEN is a fine first effort by Olympus, good image quality and it's nice to have interchangeable lenses, but like any first generation of any camera, it has it's oddities and just didn't do the job for me without an extraordinary amount of tweaking. I hope Leica will be the first company to produce a no compromizes camera that does exactly what I want a still camera to do.. take excellent still images, period. If I want video I use a video camera. All the Custom Mode Features that manufactures seem to believe everyone wants, do nothing to improve still image quality. Two grand seems a high price for a pocket camera, but I believe if the X1 produces what Leica promises, they'll sell as fast as Leica can produce them.
PEN pros are interchangeable lenses, HD video capure, now available, sane price; PEN cons: smaller sensor... others? X1 pros are aperture and shutter-speed dials, Leica optics, larger sensor; X1 cons are high price point, and it's not yet available.
Also, I don't care for a lens that retracts on shutoff, because it: * is a dust trap, * prevents use of lens filters and hoods (shades against flare), * delays startup time, and * needlessly consumes battery power.
That said, I still favor the X1. I greatly enjoy the D-LUX 3 and 4, after having had many LUMIX models. Available light performance should be great.