At this point you can get quite decent 4k projectors for around $1000. Also usable during the day (though less ideal). For us it was the difference between 3000 and 4000 lumens. Pretty silent too.

The problem with cheap 4k projectors is that they are pixel-shifted 1080p projectors. Combine that with DLPs colorwheel tech, and you are relying persistence-of-vision to combine at least 12 frames into one image. It's kinda neat that it works at all, but if you are sensitive for temporal hijinks then its not great solution to all-day use.