I've tried inexpensive servos from that company whose name rhymes with Hobby Sting, and then I bought extras because some were DOA, and then I learned to never put them in a plane I didn't feel like crashing ;-)
So I decided to give these a try anyway. What can I say, I am a cheapskate sometimes!
All I can say is, WOW! These are strong, quiet, center consistently, no jitters. I've got a few flights on them now and am very impressed. I have them in an e-flite Cub 450, and they blow away the loud, jittery, fragile DS76s that were recommended, and 4 of these cost less than 1 DS76.
I will admit that I did not have enough faith to put them in a brand new, quality plane at first. The Cub had seen some hard times before it had ever got off the ground so I decided to take all the expensive e-flite parts I had bought, put them in a Taylorcraft 450, and just outfit the Cub with the "cheap" stuff. I wish I had all my e-flite packaging because I would get a refund on it and use these in the Taylorcraft, too.