A friend has used them in a Rookie on the elevons and canards no problem.

I put them in a Roo on all control surfaces no problem EVEN on the canards which I added to the Roo and made functional.

The very early ones needed an update to run two on a Y cable with Futaba PCM Rx.
They were fine two on a Y with futaba PPM (FM) Rx.

If you look hard enough you will find that somebody, somewhere, has had a problem with a servo even high end JR and Futaba.