I've tried a bunch of 'em, though not the Cartridge Man. Today I'm happy with the Ortofon DS-3. Reads to .01g
Mine maintains its accuracy, at least according to a calibration weight. Bought from Japan via ebay, <$100 shipped.
There's a one million dollar question! Another question might be who needs +/- 0.001 accuracy.
I have always assumed the Shure SFG-2 to be accurate (it's just a pain IMO to use). When I got the Ortofon DS-3, I compared its readings to the SFG-2. And, to the degree I can determine by reading the SFG-2 scale, my Ortofon is dead on. I called it a day at that point.
In this case I follow the Casio versus Rolex argument - my $20 miniature goldsmith scale used with an old double bent credit card is accurate to .01 g. I have found that a gold credit card is not more accurate the fuel point card.