[bojan]

Well, any guider is basically a close loop system.
In order for such a system to be unconditionally stable, the open loop gain must be lower that 1.
Also, there are some other loop parameters, like phase lag and loop damping, and first of all, the type of the system (does it contain PID element or not etc.. in other words: open loop transfer function)
They all must be set properly otherwise the system will either tend to oscillate (show overshots) or the tracking will not be adequate (sluggish, not reactive enough or with ever present error).
They will be different from case to case, and they depend on the detector gain (guide camera resolution - arcsec/pixel), mass of the telescope, the way speed of the motor is changing (time delay, the presence of acceleration etc).
I think the proof is in the pudding here.. Also I imagine various softwares will behave differently on different mounts and setups.
All that are just my deliberations.. before really biting a bullet :-)