One big advantage that these types have over the FWC is that they don't slide into the bed and you get the utility of a standard shell in one. Now this won't apply for everyone, but I use the functionality of the shell a ton for skiing, hunting, etc times when I may not actively be camping. With the FWC installed you don't have much room on the inside for these kind of activities. Obviously you can take out the FWC, but then you don't have any shell and having dog crates or something in the back leaves them exposed. You can also used some type of drawers in conjunction with the camper that you can't with the FWC.
There are also the pop-top that are FWC like the OVRLND or there are a few companies (AT, Go Fast, Vagabond) that make the wedge style pop-ups. Either of those I'd think would be less work to setup than the full flippac style.
I agree that you get a two-for-one in the AT Habitat/Summit because it still retains the shell aspect of the system and I have certainly come to love that with my Snugtop. I will say that the build quality and durability of the aluminum construction versus that of the fiberglass on the traditional camper is also a major plus.
The major drawback to the FWC is having to take it on and off every time we want to use it. If the PW were already a dedicated rig and not used on a almost daily basis then I wouldn't care as much, but that is not the case at the moment. Also, if it were to be a dedicated rig, I'd still much prefer to have a diesel flatbed with a flatbed model FWC in every way. Again, that is not the case and Smolich Motors is a joke and have dropped the ball on the last AEV Tray Truck that I had held with them.
I was leaning towards keeping my Snugtop on and adding a Cargo Glide sliding tray to the bed to mount a few items and then tow the adventure trailer (what she wanted not more than 72 hours ago) behind it when needed since that seemed to be the route that the other half wanted to go. But now she throws this wrench in my fan and convolutes everything I had come to expect and plan for up to this point lol.
If it were my call I would go with the FWC from a usability standpoint, but I can't afford to go against the grain with the person I share my home with lol. She hates how they look, how they add weight up high, the need to store it somewhere (at the moment that would require a trip to the ranch one hour away) and the fact that we would be perpetually taking it and the camper on and off adding time to our prep and likely damage to the truck, FWC, and the shell over time.
Neither of us are fans of the traditional RTT and with my injury and both us down on energy and strength, climbing around on top of the PW to setup and take down the tent isn't something we are willing to hassle with any longer. Like we have said many times before, there is no perfect solution and all options have their inherent drawbacks, but for now it looks like we are back to the drawing board, ugh.