The ViewSonic PA503S vs Optoma GT5600 comparison proves that these projectors have many common features. Based on our rating, PA503S has a total rating of 5.6 out of 10 versus 8 for GT5600.
Advantages ViewSonic PA503S over Optoma GT5600
Bigger projection screen size: 30-300 inch vs 80-100 inch
Lower power consumption, 260 W vs 285 W
Longer lamp life (normal mode): 5000 vs 4000 hours