I have not used the servo recoil yet, but have 2 shermans which I will be installing them on over the winter I think.
I have 3 of these Taigen recoil units, and all seem good. The weak spot seems to be the micro switch which controls the motor that winds the barrel back into place. I replaced the ones on mine with direct replacement units from RS, and now they are very reliable. I like the way they pull the barrel back sharply on firing, and then slowly wind it back into place.
Like I said I will have a better comparison when I have installed servos in the Shermans.
all the best