I was lucky enough to receive my Sigma 150-600 lens last week. I've been very impressed with the picture quality of it paired with my Canon 7DMKII. Yes, it's big and heavy, but with my Blackrapid Sport sling, it is surprisingly easy to spend several hours walking around the zoo. A monopod helps, but even handheld I'm getting good results--which speaks well of the optical stabilization. Weather sealing is important to me. In July I'm going on safari in Africa and am told it can get very dusty, so I'd hate the build quality of my 7DMKII to go to waste. The lens and camera with battery grip fit perfectly into a Thinktank Glass Taxi. As far as I can tell, the lens is sharp, the autofocus fast, and the build quality is simply amazing. I'm in love. Sorry, wife.