Hi. I know 550D isn't here yet, so for sake of the argument let's assume IQ is similar to 7D (regardless of fps, viewfinder e.t.c.). Now, I mostly shoot landscapes, macro and portraits, max ISO about 800, tripod, I am sure I will use video once I have it. Shooting in RAW and PP all the time. I had 40D, 5D, got fed up with weight and size, now I am looking for anything smaller, lighter with good IQ. Both systems has their pro and con, as I see it:
Canon - bigger sensor, more MP, more lenses, better high ISO, better LCD (but not swivel), smaller DOF (if needed), less difraction
Panasonic - bigger VF (but dead in low light), more possibility of future progress (or am I wrong here?), swivel LCD, better bracketing option, AF in video, better DOF preview, more alternate lens options
Price-wise they both came very close to each other, size and weight are both acceptable. My main concern is DOF (I like to be able t control it) and color/sharpness quality. I like Canons, never tried Panasonic, Canon looks better on paper spec-wise, but Panasonic with 4/3 sensor has brighter future. Anybody's welcome to share your point of view, thanks for that.