This company has building similar units for over 40 years.
Capri CampersI like the looks of my unit better, but it sure doesn't have 6 foot 5 inch headroom.
Plus it is a topper not a camper.(Disclaimer to avoid angry replies)

My truck WITH topper gets 25 mpg on regular gas!  That alone makes it beautiful in my view.
Also note the driver is in the middle of my rig.   Plus it has coil springs all around which means the best and quietest ride I've ever had even counting the cars we've owned.