I have used many different Chinese Servos. Most are just fine, so I normally swear by these things... Looking back, I just wanted to share what I noticed. It rings true on both the good and the bad experiences I have had.
You have THREE types of Chinese servos...
Those made in China for American companies. - Very pricey, and yes they're good.
Those made in China branded by a Chinese company - Normally super cheap, but also very good.
and those made in China as clones or unbranded units. - Crapshoot.
Regardless of whether you are Horizon, Futaba, Goldwing or Turnigy, you have a name that was not FREE, but is valuable. You would not then deliberately produce shoddy devices and sell them under your name. If you clone something, you have nothing to loose by negatives reflecting on (let's face it...) someone else's name.
That said, consider Chinese servos to be just like any other servos. AN UNKNOWN QUALITY. Bad stuff happens, and you consider the level of support you may get when it does.
Even a highly specialized expensive servo might have a flaw... That flaw can cost you a model.... If the servo is a huge rudder servo for $150, it will probably go into a $3000 plane. If it breaks would the servo company replace the plane?
Lets look at something I swear by, Turnigy servos.
Turnigy is a brand, with pro pilots, marketing, and some degree of brand loyalty and identity. They are part and partisan of Hobbyking, and Hobbyking will take care of their customers... (Albeit not to the degree of some companies... so your $150 servo costs $30, and if it fries, you can get a new one as long as you pay the shipping....) Would they buy you a plane? No way... but if there is a reasonable solution they can do that you'd be happy with, they will protect their name.
I follow simple rules. If I buy servos, I buy Chinese ALWAYS, and I buy a few extra. In the ruder example, I could have bought 1 x $150 servo or what I DID and buy 2 x $30 Chinese name-brand servos. I'm certain that BOTH will not fail, and I am 95% confident that NEITHER will fail.
If you do buy servos direct from China, buy ones from authorized sellers or Chinese branded servos. It is unlikely someone would slap a Turnigy sticker on an ESC when they could just as easily slap a CASTLE one on it, so if you get a Turnigy servo, it is more likely to be "real" than say a "Spektrum Receiver" off ebay.
Chinese brands that I have come to trust explicitly on servos are Turnigy, Corona and Bluebird. They for me at least have been good, reliable, and sturdy.
Good luck all and please share