The BP Marcus Bühler has an A6498 inside. That is the "farm tractor" of the movements, extreme robust and nearly undestroyable. So be cool and enjoy this watch!
The 5009 has the new A52010 movement inside (also called Liaoning Peacock SL6601). Domi (a german rep modder) already serviced one of this movements. Also the german user chris3007 has already complete disassembled and assembled again this movement. He told us this is a very solid movement, easy to service, no complicated parts inside, but hard to find spare parts:
https://forum.replica-watch.info/vb...e-the-clone-A52010-movement-a-full-break-down
My opinion is: this movement isn't bad, although some users here speak negative about ZF using this movement for their BPs and the QC of ZF. My two 52010 are running fine, one of them since months now. You can give this movement to a local watch smith for service/oiling after receiving the watch. Just to be assured there is no problem with the movement and/or the QC of ZF. A normal watch smith should be able to do this.
Oh, I see, you are german: just give it to chris3007 (mod of the german subforum) and let him do a service on it. That's easy and cheap.