I haven't sold my Canon stuff yet but, I did notice a gigantic difference yesterday toting around the GX7, which I had around my neck, and the 7D + grip + Sigma 50-150 + 1.4 extender I was also carrying around. I got some great shots with the GX7, which is to be expected since I've had very good success with this camera for a wide variety of photography. But I started a switch to mu43 recently by starting out with a GX7, the PanaLeica 25/1.4 and the Lumix 14/2.5 with the idea it would replace all my APS-C gear. I gave my 11 year old the GX7 and had her take shots of the 4x200m relay handoff while I used the 7D + telephoto. At 1/8000s, the quality is not what you can get at slower shutter speeds (1/2000-1/4000) but with the 25/1.4 she got this with the GX7: The GX7's C-AF worked fine in this relatively wide-angle shot and the fps certainly didn't sound like the guy with the whirring 1Dx standing next to me. But with the right timing, even the GX7 could be considered a "sports" camera. I did notice, however, in editing the APS-C and mu43 images side-by-side that I simply have less latitude with the mu43 images. I can't push them very far in one direction or the other before things start breaking down. But if I get the exposure very nearly correct, it doesn't make that much difference. You only really need a lot of latitude if you shoot sloppily and rely on PP to fix your misses in the field. I'm seriously considering going on to the next level and getting a GH4 since it seems Panasonic is coming out with a 300mm equivalent later in the year. I really enjoy the compactness of the cameras and especially the lightness of the lenses. I had thought at the outset of this that it would be an all-or-nothing move. I know there's a lot of talk about people selling all their FF or APS-C and going mu43 full-bore. But if you do any amount of sports, I would caution against that. It seems the mu43 cameras (and more importantly: the images themselves) are more than capable of withstanding demanding conditions in the field but there is still something to be said for a larger sensor and a larger, heavier lens. The trade-off may be acceptable for some but I would hope the discussion about moving to mu43 could be more about "how does this format fit a certain amount of my photography?" I'm not convinced it's a wash between APS-C and mu43. I'll probably end up selling off my APS-C gear at some point but the fact of the matter is: APS-C and FF shouldn't be going anywhere because they still have a lot to contribute to your photography in certain areas. EDIT: Here's another shot of our State Champion (and soon to be 2-time State Champion) Boys 4x100m relay team, also taken by my 11 year-old daughter with the GX7 + PanaLeica.