I have not yet bought a mFT system (but plan to shortly) I did shoot with the Canon 7D and the 100-400, both have been sold in my decision to go much lighter. I actually sold the 100-400 some time ago because of two things 1) I never liked the push/pull lens and 2) for BIF photography the 400mm f5.6 was easier to handhold and was a good deal sharper. Of course I gave up a lot, but the 70-200mm f4 made up for a big chunk of that. The really hard part (and the one that I have really struggled with) is just saying goodbye to the DSLR concept. I am sure many on this site faced a similar dilemma and felt the same amount of angst. One of the reasons I have been visiting here is to learn about the mFT systems, before making a purchase. Though, I am pretty sure that I will go with the OM-D. From what I've seen posted here and on various other photo sites, demonstrates that the IQ of the mFT is excellent. And, it appears that there is a lens for just about everyone's preference. Will I miss the DSLR? Probably at times, but at my age size and weight are more important, particularly when I travel Good luck on whichever route you take.