How about a servo comparison test by RCU??
I don't necessarily agree that a test will be biased. Car and Driver, for example, does reviews and comparisons between cars in the same class every issue. It is arguable that Car and Driver lives off subscription fees more than ads, but I rarely see ads on RCU that are placed directly from servo manufacturers. Not saying that it WON't be biased, just not necessarily.
Or if not a comparison between manufacturers, at least a test on whether the servos really live up to their specs, or like MonkeyBoy said, gear train wear, % error on real output vs signal input. I don't think a test like this really makes a servo stand above another, just provides consumer with more information. Of course a 50K Vette will be better than than a Honda Civic, but is the Vette really worth 50K? kind of stuff.