Personally I prefer the 5D Mark III's image, but the D5200 delivers WAY more value. The image is close yet the thing costs $700!
I am planning a day light shoot yes. Though to be honest, you can tell a lot more from the low light images because of the way the tonality and lighting is. One thing that I do need to do a day light test for however is dynamic range. A tunnel test. The GH3 and 5D Mark III can both shoot flatter than the D5200 without a load of banding being visible. Generally though, I find all the DSLRs to be pretty similar when it comes to dynamic range. As soon as you grade the image they all have about 9 USABLE stops. Nobody likes the look of an ungraded flat CineStyle image, you're trading other attributes for the ability to place your 9 stops in a different spot, that's all.
The dilemma at the moment is that the BMCC is so nice in raw that it leaves all the other cameras looking a bit too digital.
I highly recommend experimenting with Film Convert and Film Stocks plugins for Premiere to give the compressed footage more grain and a more authentic film look.