used Corona DS939 and DS929 for 3 yrs. Both have more torque than mg90S or mg90 (I only used mg90 which has more torque but slower than 90S). work very well. especially 939 which is digital and has more torque than 929. torque on 929 is on par with mg90 but slower. I think for the price difference I would just get 939. You will find they are a lot quieter than towerpro too. use 6V BEC with them you will like it.
as for the jitter from towerpro, I am not sure it is all about the circuitry. I have used quite a few towerpro mg90 for my heli cyclic before start using 939/929 (never used 90S, torque is weak while not quite fast enough for tail servo) I think part of that is signal noises interference. Some times I switch a different ESC or add a ferrite ring will get rid of it.
I still have some mg90 servos on one or two of my heli, they are fine. I do have about a dozen case/flange damaged towerpro mg90 (by heli crashes
![Razz :P](./images/smilies/icon_razz.gif)
) in my box, now I use them for planes.
![Wink ;)](./images/smilies/icon_e_wink.gif)
their metal gear is very strong/resistant to crashes. For all the mg90 servos I have, most of the time it is the case got damaged, not the gear/motor. I think the case will break before the gear/motor.
If high torque is not much a deal but speed is , check out the MD922 and DS919 both has similar torque as mg90S. Both are quieter than towerpro too. MD922 is the smoothest one. among all these. I can use MD922 for either my 450 cyclic or as tail servo.
PS: My Skyfun delta wing has two DS939 in there, each balsa aileron is one foot long 1 inch wide. They can handle anything I put on the aileron.