I have three Canon DSLR cameras, 7D and 7D2 crop formats and 5D2 full frame.
I use a 7D2 and a 7D with 17-55mm f/2.8 IS and 70-200mm f/4L IS lenses for general and travel photography. I also carry the 1.4X TC III on my travels to increase the telephoto lens to 98-280mm. IQ is very good to excellent and I can focus with all focus points.
I use a 5D2 with the 70-200mm f/4L IS lens for portraits of both people and my dogs.
Finally for venues in which I need telephoto lenses, (sports, wildlife, airshows, etc) I use the 7D2 with the 100-400mm f/4.5-5.6L IS II lens and the 5D2 with 70-200mm f/4L IS lens which gives me an equivalent 70-200mm and 160-640mm range. Ad my 1.4x TC to the longer lens and I get a far longer focal range 224-896mm.
All these combinations give me excellent image quality - even with the 1.4x TC III. I can achieve auto focus using the center spot focus with the 7D2 and 100=400mm f/4.5-5.6L IS II lens.
I am quite content with the 7D2 but, would like a 5D3 or 5D4...
Update... I have recently been quite happy with the 5D2 wearing the 70-200mm f/4L IS lens along with the 7D2 wearing the 17-55mm f/2.8 IS for non-sports or wildlife, walk around events. This gives me an equivalent 27.2mm to 200mm range...
Since I originally posted to this thread, I have purchased a 6D Mark II to replace the 5D Mark II with better AF capability and at least as good IQ. I have fallen in love with the fully articulating LCD screen on the 6D2.