As a person who owns a truck camper they can be a bit much for many people to deal with.
You have to match the camper to the truck, get used to top heavy handling characteristics of the hard sides,
understand that removal is often forbidden in various places and in many instances won't be anywhere near easy if the site is not hard and level.
It is beneficial in that if you have need for a truck anyway and plan on towing the truck camper can make all kind of sense.
(I tow a boat) But if you don't do research and completely understand the physics, load characteristics and so on you can risk being totally dissatisfied at the least and dangerous at the other end.
Truck campers are also not really suited to more than a couple of people even if they have slide outs. They are very small living quarters.
But if you are comfortable with their room, you can get very capable vehicles for camping, boondocking and access into places that other RV's can't.
Class B vans and Truck campers are really kindred in that regard, but a good size truck camper may often have better features, tank sizes, storage, etc.
Price range for Truck campers can be very wide, just as the price for the truck to haul it.
Any truck camper that is pushing 3000 pounds dry weight should be on a dually truck or highly modified 1 ton SRW.
But for that 3K lbs you get a sleeper dinette, queen bed and some type of full bath.
They aren't for everyone, but the people who own them typically know what they are looking for.
I would also recommend that if you buy new, you do so from a company that deals with a lot of them. Most RV store salespeople are not trained and do not understand anything about them other than a possible sale.
DB