We need to be very careful here about what we allow to be called a 4K projector. Nothing from JVC, Epson, Optoma or BenQ (sans top of the line offerings at JVC) is actually 4K. Pixel wiggling and similar technologies are all fauxK not 4K.
The Vivitek is actually a DLP (which means it's a 1080p projector, using the same as pixel wiggling, but with mirror shifting to get 4K). What this means is that you do get 4K pixels per frame of a video, but it's 2K then 2K, which is not nearly as good as native. Reports from CEDIA stated that nobody was really able to stand up to Sony other than JVC's 35K laser/true 4K model, and Sony's 885ES was superior in the view of most attendees.
The Vivitek is actually a DLP (which means it's a 1080p projector, using the same as pixel wiggling, but with mirror shifting to get 4K). What this means is that you do get 4K pixels per frame of a video, but it's 2K then 2K, which is not nearly as good as native. Reports from CEDIA stated that nobody was really able to stand up to Sony other than JVC's 35K laser/true 4K model, and Sony's 885ES was superior in the view of most attendees.