On the topic of Fantastic Fan vs. Maxxair: I have had a FF in my van for years with no problem. I have a Maxxair in my Bigfoot
. I love the many speeds of the Maxxair but have had to deal with problems.
1) If the lid is not cranked up all the way it rattles in the wind.
2) After 5 years I replaced the printed circuit board, which failed due to corrosion, for $70+. I expect to replace it again some day as it is not adequately protected from the weather.
3) The design does not keep out mosquitoes. Tabs that holds the removable screen have gaps large enough that mosquitoes get through. The gap between the garnish and the face plate may also allow ingress. To solve the problem I installed removable no-see-um mesh to the garnish using Velcro on the garnish and on the mesh. I apply the no-see-um mesh when necessary. The fan works harder to move air but the bugs do not get in.
4) With the lid raised, during a downpour rain bounces off of the roof and into the fan. A steady mist enters the trailer.
5) The unit does not vent well without the fan blowing.
Despite the shortcomings I would buy the Maxxair again. I like the low profile when the lid is closed. For the FF to be open in the rain requires a high-profile vent cover. Rain may blow through the louvres on those covers when the wind is blowing from behind the trailer. The Maxxair under-lid area, prone to mold, is easy to clean by unhooking the raising mechanism, though you do need to be on the roof to do it.