I recently purchased a used medium Airtop and it has been on my FJ for about a month now. I have not experienced any issues with dirt, bugs or water getting in when the tent is closed yet. We just got back yesterday from 2 weeks of camping in Colorado and had rain everyday, a couple days were very heavy and we stayed dry. I even pressured washed the truck off and popped up the tent afterwards and had no water intrusion at all. The PO had to repair the tent material in a couple places due to the small holes caused by the tent material not being folded around the gas rams/arms properly. The guy used a repair tape that is made for the Sunbrella tent/awning material and so far is doing the trick. He also claimed that the tent was delivered to them that way, and when I picked up the tent from him he spent a few minutes with me to show me the proper way to fold the material around the lift mechanism. It's not hard to get it folded correctly once you know what to look out for and we have put it up and down quite a few times now and have not had any new holes appear.
I know that 2 weeks (12 nights use) is not that much time to gauge how well this tent is going to do in the long run but overall I'am very impressed with it. Considering how much rain we encountered and the fact that we stayed dry (which also means we were never cold either) says alot. My fuel mileage is slightly better with the Airtop over the Ezi-Awn that it replaced and the setup/take down time is faster as well. We can also put all of our bedding in it, we could not do that with the Ezi-Awn and still have the cover fit properly. Still need to do the high winds test which the Ezi-Awn did very well, I'am hoping the Airtop will do as well.
2008 Toyota FJ Cruiser Trail Teams w/Autohome Airtop RTT, Old Man Emu lift, Aluminess front bumper w/Superwinch EX9, Expedition1 rear bumper w/tire carrier, BFG 255/85-16 KM2's, Baja Rack utility style, Dirty Parts dual battery system, ARB 50qt. fridge, AT 2 drawer storage box, full set Ricochet skid plates.