Don't have any, but think I might get one to see how they fit and work out with an eye toward getting a second if they are worth it. My rear seat has been in the cave since the day after I got the Jeep so it won't get one. Thinking about it, with the pouches and all included, $99 isn't really that high.
I thought about it many times, but I have no room for it in my jeep since I added the insta-trunk. Two car seats in the back seat precludes me from getting the covers for the front seats. Room in the Jeep is precious, and must be used carefully to get the most from what's there. (Get an LJ they said. Sure, if you have a spare wad of $4k laying around, I would...) Everybody that has a jeep uses it in a different way; what works for one may not work for the next, like motorcycles and tattoos. The GEAR covers fall into this category.
I've seen the tailgate panel, but I'm planning on modifying the rear tailgate to drop down instead of swing out. When that's done, the panel would (kind of) be in the way. As for the door, I have only heard of them, and haven't seen them. I'm not sure where they would fit, as the door is very close to the seat when closed. In a CJ or YJ, it would make more sense because the doors are thinner and there is more space- but a TJ has so much plastic trim in them.