C&H Precision V4 Defender RDS Mounting Plate

[Kilroys]

Any reviews on the C&H Precision V4 Defender Mounting Plate? I have a G19 MOS and would like to add a Trijicon RMR. I know C&H is recommended by many. I see they came out with the V4 Defender which adds a polymer window to protect the front of the RMR. It cost $10 more than their standard Glock MOS mounting plate (links below). Seems like a nice added layer of protection for the RMR. My only concern versus is that it's made of polymer instead of aluminum and according to one review the screws will need to be adjusted/reevaluated after break-in. Any feedback is appreciated.

http://chpws.com/product/v4-defender-glock-mos-to-trijicon-rmr-type-1-2

http://chpws.com/product/v4-mil-leo-glock-mos-to-trijicon-rmr-holosun-407c-407c-v2-507c-507c-v2-508t-and-508t-v2