I've not tried the wallplate version but I have one of monoprice's earlier standard hdmi over 1 cat 5 cable extenders. I had this running from Zone 4 on my Denon 4520 to a TV outdoors (salt air environment)and it worked perfectly.

Temp.setup - 2.1 - Denon 1713 AVR, Denon 1713 BRD, Paradigm Cinema 200, and Monitor Audio 360 Sub