I have a '99 F250 with an ATC cab high and a '05 Tacoma with a SnugTop cab high. I with I would have gotten the side windows to both have a sliding screen window and open completely (windoor) to get better access to the front of the bed.
You need a locking tailgate to help in security even though if anyone wanted to get something inside, they could break in. Lock boxes inside help as well.
The Ford's is white (much cooler) and the Tacoma's is black (hot).
I have Yakima racks on both. I could not tell any mileage difference with just the caps, but when I added the cross bars, baskets, kayak, bikes, etc. the mileage loss was very noticeable. Also when you add these you have to watch the awnings on drive ins (Sonic, etc.) My F250 will not fit in my standard 7' garage door with the cross bars on much less the basket.
I really like having the caps on both trucks. It does cause a bit of a problem when hauling tree limbs, compost, mulch, etc, but well worth the it when hauling my toys when traveling.