I recently replaced a static vent in the bathroom of my trailer with a vent fan and equivocated between MaxxAir and Fantastic Vent products as well as about what kinds of features to include. Even though the MaxxAir sounds in many ways to be a better, stronger , and more fully featured unit, I installed a Fantastic Fan -- 3 speed exhaust only. I added a MaxxAir vent cover so that I can use have the vent open in the rain or when traveling.
Incidentally, I remember from quite a few years ago that FF said that you could drive 60+ mph with one of their vents open so long as it was in the full open position.
The reason I chose FF over MaxxAir for the fan is that I saw in a couple of posts that MaxxAir had been bought by a larger company and that it was hard to get information or parts for their products. FF, on the other hand always had great customer service. I do note, however, that they are now owned by Dometic so that may have changed.