You can get a good idea by looking at Kristofer Rowes flicker account. He shots the 7dm2 and 1d mk4 so he has plenty of photos to compare. I have the 7dm2 and the 1dx and there no comparison in my opinion that the 1dx is way better. Again thats just from my experience of using both. I only use the 7dm2 if the light is really good, then it performs great. I know losing the 1.6 crop is alot but if you expose properly I can crop a ton and get clean images with the 1dx. I can also shoot at 10000 ISO and come out with a clean image if you dont have to crop much. All I can say is if I had to only have one I would choose the 1d bodies. Now I know I am comparing it to a 1dx not a 1d mk4 but I got friends that have the 1d mk4 and there high iso are very clean. And Every one says the 7dm2 focus system is awesome which it is. I still think the 1d bodies focus better at least for how I shoot. I would ask kris his opinion as on the 2 since he shoots both. Something tells me prefers the 1.6 crop factor though. Good luck in your choice as I dont think you can go wrong either way.