So i got the 4K device from gearbest (7 days from HKG) and returned non 4K version to the Mi Store - had to forefeet 10% reduction in refund price as i had used it!
My First impressions between the two - might be useful for those considering which one or maybe a swap.
The Noise level on the 4k version is at min 10 DB louder than the International (non 4K) version.
The interface on the 4k is worse vs the international version (mostly because the Chinese UI) (English translation aside) . So android 9 is way better.on the International Version.
Keystone correction (OMG) i thought it had 8 point on the 4K vs the International Version, but turns out its even worse, it doesn't have any real keystone correction, you can tilt up or down with some wired adjustment - which is totally terrible, the non 4K international version has 4 keystone corrections and is better.
3D plays - but for some reason i cant get my Acer 3D (E4W) DLP link glasses to work - i read some earlier posts about some Glasses not working - i'm still testing and dont know why some work and dont work - seems odd.
4k is obviously a plus but TBH i ran them side by side for an hr (before i had to take the other back to the store), and since most stuff is in 1080p i'm not sure if the move has been worth it from a $$ perspective, again i have a large 3D collection so getting that working is key for me, but having to fork more $ out on new glasses for this projector, also kinda defeats the object.
I have a Optima UST fixed screen and both projectors worked very well, if i play 4k content it does beat the non 4k version for sure.
hope this helps others.
Im interested in which 3D glasses anyone has got working on the 4k version