CG,
I use Airtronics servos on my JR X9303 (with Spektrum receiver) and had no issues at all. They were a mix of both older and new Airtronics servos and they all worked just fine. The new ones had Z-connectors that plugged straight into the receiver, but on the older servos I had to use the pigtail converter that Airtronics has to go from Airtronics old to Z.

Ken