JLC "have" multiple factories, ie. they outsource board production to one of a number of third parties. You are mostly exposed to this with boards that do not have SMT components, since AFAIK SMT will automatically route your PCB to the SMT-capable PCBA (one factory only).
I am really nonplussed with them recently for a number of reasons and have begun to reach out to PCBAs here in China independently. As I would prefer to have a decent frontend for handing off work (quote, pay, support, etc.) I hacked one together last night. Let me know here if anyone else would like such a service. Ideally you pick your own PCBA and both parties communicate via the platform. Conceptually reputation should accrue with volume, with turnaround times and quality issues recorded publicly.
I am really nonplussed with them recently for a number of reasons and have begun to reach out to PCBAs here in China independently. As I would prefer to have a decent frontend for handing off work (quote, pay, support, etc.) I hacked one together last night. Let me know here if anyone else would like such a service. Ideally you pick your own PCBA and both parties communicate via the platform. Conceptually reputation should accrue with volume, with turnaround times and quality issues recorded publicly.