I agree that the fan on the Vava is obnoxiously loud, at least the high level fan noise. I'm hoping that in the winter time, when the ambient temperature in my room is much lower than in the summer, the Vava fan will not have to resort to the high level to cool the projector, so hopefully it'll stay at the lower level and therefore less noisy.
I would say that their interface, especially their Android TV version, is garbage. I had to buy an Nvidia Shield TV to use as a source, because the Vava Android TV version is a joke and really unusable.
Ditto on booting up to the same HDMI channel from last time.
And where's the promised firmware upgrade to enable 3D movies???
The 4K is awesome! HDR handling is mediocre at best, if any.
My projection image is not 100% square at the bottom edges no matter how I try to adjust it. It curves up a little bit. No significantly, but definitely noticeable.