Well for your pros and cons list. Hmmmm
Pros.... a lot more gas. We did a trip from south eastern CT to upstate NY 6.5 hrs travel one way.
We then drove around up there several places about 4 days and then came home. 15.5K fifth wheel 4 guys and fishing gear.
Made it all the way home and still had more than half a tank. Less time worrying about filling up more time having fun.
Cons... well the loss of bed space. All depends on what you pack and what you carry.
We personally don't use the bed very much. We place our pads for under the jacks in there and depending on the weather if it's raining the power cord, hoses and stuff go in there as well. Other than that it's empty. So that didn't effect us either.
This is the second one we have had from transfer flow and each one fit under our tonnue cover. Last one was a truck box/ gas tank combo.
We don't take a lot along with us on trips basically just what we need and the 5er is always packed so hard to forget anything.
That is why we went with the in bed unit.