I started using the cube a few weeks ago and so far no complaints. It seemed to do pretty good recovering extra fine beach gold out of very heavy black sand. Only thing I noticed is really thin flat gold seems to travel on the mat some. I'm using the four stack and found a picker on the top part of the last tray. When I looked at it close, the gold was really thin, so if thats the kind of stuff you might be running, make sure you get a four stack and check the bottom tray occasionally to make sure you aren't losing any flat stuff. Other than that I love it! Cuts my work to nearly nothing. Wish I would have bought it sooner.
After I run beach sand through the cube I still like to run it's cons on my Black Magic since it's a royal pain trying to pan that super fine stuff out. Great investments! Time is money, and those two together save me tons of it! A little pricey, but I look at it as an investment, one I'm glad I made.