I've been running a dieselcraft and a copy for about two years now. The ebay one is like my copy and it works near as well as the dieselcraft. My oil is pretty clear looking before I filter it. I pour through a restaurant fryer cone filter to get out the big chunks that can clog the centrifuge. As I can't see the difference between oil filtered to 5 micron or .5 micron, I just run the centrifuge in my 55 gal drum (about 45 gallons of oil) for about 12 hours. It may cost a few extra pennies in electricity (although I did just do a full batch off of the electricity from my 6/1) but I know my oil is clean. I run a 1980 240d, 1984 300sd, and a 1995 6.5 turbo diesel suburban. I get several thousand miles from a filter, and I think most of the clogging is from thicker fats and oil, not dirt.
If you have any questions about what I do or why, please ask. I've gotten so much from this forum, I'd like to be able to contribute.
Oh, when I ran the 6/1 to power the centrifuge, I used a 50/50 mix WVO/diesel.