I think the answer for everyone who makes a decision for 5er vs TT rests in the intended purpose for the truck bed. So, putting aside the type of camper you're considering, what are your plans for your truck bed? If you want to get a shell or a cover for the bed, you won't want a 5er. What will you use the truck for when you are not traveling? Do you haul anything, need the bed of the truck for carrying lumber, furniture, dirt, gravel, construction, farming? Or do you have the truck JUST to tow a trailer? If you have no other intended purpose for your truck, then I suggest a 5er. However, if you use the bed of the truck for any number of "other" things, you won't want that 5er hitch in your truck bed. Even if you get a quick disconnect type 5er hitch, you still have the weight, the holes for anchoring, and all the logistics to remove it from the bed. A travel trailer hitch is easily removed, and tucked away in a corner.
For me, I use the bed of my truck to haul too much other than my travel trailer. I have a construction grade shell on the truck bed with side panels, each side has 2 shelves the full length of the bed (that's 32 feet of shelf space) in that shell. My shell also has a ladder rack. I carry our canoe on the rack and all the canoe peripherals are stored on one side of those shelves (paddles, life jackets, seat cushions, anchor, rope, outriggers, sealed container for hold personal items, and a whole lot more). That still leaves the other side empty for camping items, like tools, hardware, stuff I use at home and when camping. Then there is still the bed of the truck left to carry the blue sewer tote, a 7 foot step ladder, fire wood (which stays dry when it rains), the spare tire for the trailer, extra water jugs, my extra DEF fluid for the truck, a carriage for our dog, extra lumber for leveling the camper.
The bed of my truck is 8' 2" and wide enough a 4x8 sheet of plywood will lay flat between the wheel wells. The shell can be removed when needed and I still have full function of the truck bed.
So the answer to your question, (In my opinion) rests in what is your intended purpose for the bed of your truck (when not camping)??? Figure that out, and I think you have your answer.