I have a GM1 and a Canon 7D. I find myself using my GM1 more and more because of its size and weight. I take it along when I'm doing other things or traveling. I tend to take my 7D if I'm going on an outing that's focused specifically on photography or for sports/birds. I'm just curious how many of you are exclusively MFT and, of those that aren't, how much you use other cameras. What determines when you use one and when you use the other?