I'll offer the flip side of that. I have a fantastic fan in my '93 Hallmark. The dome was cracked when I bought it about 5 years ago, and it broke off when I accidentally left it open for a trip down the highway. Fantastic sent me a new dome and new lift arm at NO CHARGE. They stand behind their product YEARS after you install it.
If Maxxair does the same, then go for it, but I'll always replace vents with Fantastic units because of the excellent customer service that I received. They went out of their way to get me parts FAST, by having a local dealer hand them over, and then replacing the dealer stock. (I was leaving the next day for a trip...)
I will say that the 5-er that I now call home had a Maxxair cover on the fantastic vent when I bought it. I have it removed for now, but it was a heavy and well built piece.
And I can tell you that the normal vent with a little 5" fan offset to one side is only good for making noise and running your battery down. The 5-er has one in the bathroom, and it's useless unless you just want some white noise for "concentration".
Chris