It makes sense comparing Optoma ML750ST vs ViewSonic PX747-4K because they both are able to give some premium features. Based on our rating, ML750ST has a total rating of 7 out of 10 versus 7.3 for PX747-4K.
Advantages Optoma ML750ST over ViewSonic PX747-4K
Lower noise level, 22 dB vs 27 dB
Lower power consumption, 77 W vs 310 W
3D support
Longer lamp life (normal mode): 20000 vs 4000 hours
Advantages ViewSonic PX747-4K over Optoma ML750ST
Bring the cinematic 4K UHD experience home with the PX747-4K
Bigger projection screen size: 60-200 inch vs 30-80 inch