I sold my D300 and upgraded to a D500. If you think the D300 AF-C was good...it feels like a piker compared to the D500. The D500, in my opinion, is an evolution not just an upgrade. I've used it for all kinds of sports, a trip to Yellowstone. Nikon brought out the 300/4E PF, that and a TC14E-III got me as close as I needed to be for wildlife and sports. I pitted the Olympus EM1 Mark II against the D500, no contest, and I was even using a Tamron 70-200/2.8VC on the D500 and the 40-150/2.8 on the EM1 Mark II. I do run multiple kits and take the gear I need for the shoot I am going to do. If it is sports or weddings, I'm going with the D500 and D700. For everything else, I can be very happy with my m43 kit of EM5 Mark II and PEN-F. Best thing to do is to rent or borrow what you don't already have and see if it gets you where you need to be. I'll throw some links to my relevant reviews below. Yellowstone Compendium Post Best Light Photographic BLOG: A Trip to Yellowstone National Park - Compendium Post D500 - First Look Best Light Photographic BLOG: Nikon D500 Review - First Look Olympus EM1 Mark II versus Nikon D500 - Columbus Blue Jackets Hockey Best Light Photographic BLOG: Head To Head - Olympus EM1 Mark II Versus Nikon D500 Shooting Hockey I'd be happy to lend any further information if you need it.