I currently use a D5200. I've owned it for a year and its suiting me quite well. Videography is my side business and every client I've had has been quite pleased. I doubt I will be needing 4k for a while so 1080p is fine with me (I also don't want to push my 2012 15" Macbook Pro Retina with 8gb of ram too much and I don't use proxy editing.) My main lens is a tamron 17-50 f 2.8. Basically I'm just scoping out my next camera. Currently it looks like with the D750 I would be getting a few things that I lack on my d5200 namely: Live View Aperature Switching, Flat Profile, Upgraded Image?, good in low light (vs gh4) and slow motion 60p. I know there are better slow motion cameras out there but that would require to use an adapter. I guess the other camera I'm considering in the price range is the GH4. I mainly am interested in the GH4 because of its lack of recording time limit. That which I sometimes run into on the d5200. Not a huge deal but it would make my job easier sometimes when its needed. I would love to move to a more traditional video style body like a c100 mainly for audio inputs, for me its annoying to sync in post even though its very easy in Premiere to do so, but I sometimes do stills as well. So would a D750 be worth it over the GH4 for a solid 1080p image? Or should I even consider an upgrade to d5500 body if I just want to add FLAT and 60p but save some money? I should add finally that my projects are all over the place... sometimes corporate, sometimes music video, sometimes still interview. I also need to invest in better lighting for controlled shoots but I own a basic light kit that does ok.