Tuning servos isn't that bad, provided you have the required information available, which unfortunately, Mach and CS-Labs don't make available, and have you mostly rely on their auto-tune functionality to get something that hopefully works.
Galil does have good tuning functionality, provided you spend $200 on their Galil Development Kit (this kind of thing I hate, whereby you pay good money for a product, then have to pay extra to be able to use what is essentially a key feature of the product. It's not like you're going to buy an analogue controller, and then not want to tune the servos..)

Tune by ear is a load of rubbish, apart from it letting you know tuning is majorly off as you can hear the motor oscillating!

To get a bit better understanding, it's probably worth reading these pages of the Dynomotion manual-
https://dynomotion.com/Help/StepScreen/StepScreen.htm
https://dynomotion.com/Help/BodeScreen/BodeScreen.htm
https://dynomotion.com/Help/FilterSc...lterScreen.htm
Although they are KMotion specific, I think they explain the fundamentals behind servo tuning very well.