That site's review page won't load for me in Netscape or IE. I'm not too concerned that any copper paste will outperform Arctic Silver. Copper paste is terminally electrically conductive, for starters. Except in a very thin layer, under extreme pressure, the Arctic Silver isn't electrically conductive. Someone at overclockers.com tested the Arctic Silver for electrical conductivity with a Multimeter. It registered infinity. I dunno what "extreme pressure" really means. However, copper bearing paste needs no pressure at all. Put an Ohm meter's leads at two ends of a dab of copper paste, just like the reviewer did with AS. Ping! You've got continuity.
There's nothing wrong with copper paste. Just be VERY careful if you use it.