All the UST laser Chinese projectors are so-so, at best. Lots of complaints about image quality compared to what you hear from Epson. So, no question, I would get the Epson 5050 in a second. The JVC is a nice option, feel free to shoot me a message if you want pricing. Likewise, the JVC RS540 may be right within your budget and would be a very significant upgrade over any of these options. Might need a couple hundred more, but not much, to get there.
No way I would get a UST 4K DLP model. The quality just isn't there yet.