I joined Mu-43 roughly a year ago (May 30th to be exact). I came to m43 from a Canon G1X for a couple of unlikely reasons, the Olympus brand name and the 4/3 50-200 f2.8-3.5. I realize the whole Oly brand name seems sort of hokey, but a long time ago when I had a bag full of SLR gear (Pentax) it was the camera I wanted and could not afford. So basically instead of buying a Mustang I bought an E-M5. Ok not really :smile: . I did want to take more pictures of my kids sports and I having had a big bag of SLR gear including motor drives and telephoto lenses, I realized I did not want to lug a lot of gear around. Totally by accident I read about the Oly 50-200. I bought it even before I had a body! The bottom line was I wanted a faster operating camera than the G1X (not hard to achieve!), that had more reach and was still compact. I had originally thought I would buy a 7D + L Glass, and keep the G1X as a travel camera, but the 7D was just too big. And, then I quickly bought too many lenses including the 12-60 and 14-54II. I knew this was going to happen, dammit, which is one reason I didn't want an ILC at all. Then the reality check point occurred . AF was not anywhere near viable with the 50-200 and the E-M5. Luckily, the big summer sport for my kids is flatwater paddling and it is a relatively predictable sport, so MF can be done, barely. Then the E-M1 came out! Queue the fanfare and dancing persons! (have to be PC!). It certainly works better with 4/3 glass. Much better. But it is bigger than the E-M5, really small DSLR size. The size issue is ironic though, because the E-M5 with a grip, which you need to use the larger glass, is actually bigger and heavier than the E-M1. Somehow, though, it does not seem that way. Since I am firmly invested in m43 now, of course it is easy to rationalise the choice. However, there is not direct easy replacement for the 50-200 in other systems. For a lot of what I shoot this lens is really an elegant solution to high quality reach. M43 is steadily winning unlikely converts. A friend of mine I ran into at a photo club meeting with large bag of DSLR gear was really quite surprised with my small bag of m43 gear (Hadley small). I ran into him at a house warming a few months later and he had fully converted to the E-M1 and a nice selection of lenses. In the end smaller kit is an easy choice to make.