If you are looking for a UST projector within the $3,500 budget, you have better options than the Vava.
Optoma CinemaX-P2 @ $3,299
Samsung LSP7T @ $3,499
Both will have far superior images than the Vava, albeit at a higher price point.
When it comes to the Vava vs the Epson 5050UB, I would absolutely suggest the 5050. If you do not require/desire a UST type of setup then you will have a brighter image with greater contrast and far more versatility with the 5050.