The M43 difference for me. I have two m43 setups – EP5/Pany 14 with GWC1/Sigma 30/Oly 75-300 II and Gx8/7.5/12-35/PL100-400 on order. My EP5 is my “always with me kit” and with a second Gx8 and the PL100-400 ordered the Gx8 kit is my “serious” kit. I am getting ready for a trip to photograph snakes in S. California and Arizona for a week. About six years ago I took my D200 and a Tamron 90 in a small LowPro bag with the weather/sand cover. I’ve just packed my EP5 kit including 3 batteries and 3 SD cards in the same bag. So basically I will have 11mm to 300mm (EFov 22-600) covered. I’ll have any urban stuff or landscape stuff covered with the 14 and 30 and critters with the 75-300 (taking a Hoya 2 element +10 close-up filter for the Sigma). One day when Olympus has 4K I’ll buy the PenF(2/3) to replace the EP5 for video. But the key here, is that entire kit weighs maybe 3 pounds or so and I have a complete system which I can carry for miles at my age. There is no other system that could pack such imaging strength into such a small area. M43 has done one thing that no other system was able to do, I have hit “good enough” and like my D200 I expect everything but perhaps the EP5 as 4k video is important to last for 6 to 7 years. Maybe not a forever kit but certainly a “good enough” for what I need.