Putting the FUT vs FUE debate aside for a second, FUE will obviously produce a cleaner look 3 weeks after as you'll have no scar to cover up and your hair will all be the same length. At this stage people will just assume you shaved your head. Redness will be your only consideration at 3 week, and recipient hair will begin to shed, so disparity will creep up on you.
If you intend to shave your entire head and go FUT, the linear scar will be visible, but most of the scabbing will be gone by week 3. This is important if you want to apply a cover-up or masking agent like dermmatch or couvre on the scar, but your hair will not cover the scar until it grows an inch or two. Check out Mav23100Gunther's pics--he went FUT with Rahal and did this.
Personally, I looked terrible at 3 week FUT bc I only shaved the recipient zone. I've yet to see someone NOT shave their entire head and look decent post-surgery. If you're cool with that, its really a matter of opting for the procedure best for you.
Or what Dutchie said