I considered the AT flippac, falcon, and finch. I was close to getting the flippac and just decided where I camp it's too cold to have a tent on top. I would have put in a heater in a flippac, but didn't see a whole lot of others who had done it. It seems everyone, including FWC, says the Falcon is just too small. The finch you can sleep down below if you needed to (and aren't very tall). I put the cushions on the action packers and I could fit sleeping sideways/little diagonal in the camper in a pinch if needed
With stock suspension maybe a shell with nothing in it would be ok. It just depends on how much you end up hauling around. I will tow a dirtbike or 2 and maybe a snowmobile if possible, so I figured all around suspensio upgrade was best. The way the camper is secured seems fine and the front is super strong since it's mounted directly to the frame. Then the back has the happijac buttons with a "cushioned" turnbuckle. The rail system in the bed seems pretty weak just from my experience trying to secure dirtbikes and other stuff back there. They would always flex and seem about ready to rip out. They say rated for 250lbs or something I think though.