Our club has a 4-circuit jockey box with a cold plate that looks exactly like the one you're looking at. I bought it on eBay a bunch of years ago but I don't recall who the seller was.
I say go for it.
Our box serves beer nice and chilled, even if poured continuously. We have used it for many a Club Night, camping trip, and Brew-Ha-Ha in the sweltering summer heat. It has never served warm beer no matter how quickly we poured. We have the plate resting on a wire basket with ice packed underneath as well as on top and all sides. It helps if the beer keg is pre-chilled and setting in a bucket of ice, but it's not necessary. We have been roundly impressed with how well it chills our beers.