Hi I have a Nikon D750 with a 70-200mm f2.8 VRii lens and a 35mm f1.8G ED lens. I mostly shoot family portraits. I was thinking about switching to the Canon 5D Mark IV with a 24-70mm f/2.8L II USM Lens and a 70-200mm f/2.8L IS II USM Lens. Will there be a noticeable difference in image sharpness and color?
+1 for @user58923 answer. Adding words: 70mm can be a DX portrait lens, but it is too short for full frame. The 70-200 (at around 105 to 120 mm) is much better perspective for full frame portraits. Meaning, you always want to stand back at 7 to 10 feet for proper facial perspective. This focal length forces that distance. I don't see how you could be unhappy with the 70-200.
Color is determined by selecting proper white balance for the light, and by color profile choice. Regardless of brand, DO NOT USE VIVID or LANDSCAPE for portraits. :) Try Neutral, Portrait, or even Standard. And for the lights, get a white balance card.