I put this cap on my truck awhile back just for DOT and Thiefs. I don't have to worry about either so far. It looks like a personal truck going down the rd. Welder doesnt get any hotter with the cap on it cools just fine. The cap is all aluminum so it's easy to remove if need be. I have reels that swing out when I drop tailgate. Works great on the compression stations we weld on. Also have a 50 gallon transfer tank for fueling.
I have the drain hose for the oil run out the passenger side dually fender. My 300D has a valve in the line to drain the oil, I set the drain pan on the tires and just open the valve.
The best: would be I don't need to worry about weather getting on any of my equipment. In the most part I don't need to worry about my tools and leads coming up missing at the motel. It's easy to work out of.
The least: Honestly I really don't have anything I don't like about it. It works for me and it's easy to work out of. I'm 49 yrs old and I don't need to show off what I have or what I do for a living.
Always a hot lunch with the oven. Don't feel I need a hoosier pole with my reels. I need to get a pic of the reels and pull out draws in bed when I get time and post it.
Here in the East [Pa. & surounding] farriers often have custom truck beds. They do open from the sides and back, but all the way down to the bed floor on the sides as well as the back.