It's also worth noting that the FET's are considerably larger on the NitroPro servo as compared to the AGFrc servo.
So quick list of NitroPro upgrades that I'm aware of:
1) Upgraded FET's
2) Upgraded POT's
3) Upgraded circuit board and all the installed components
4) Redesigned case to prevent motor pinion gear from sliding off the shaft
5) Redesigned installation of the POT to prevent it from sliding out of place
Simply put, the pricing for the AGFrc branded servos is not worth what they are charging. spend the extra $40 to save you $80 of frustration, been there done that!
What's sad is that I considered selling the repaired servos, but I just can't in good faith pass forward these potential time bombs