Gap - set up by daughter of a former Lebanese American advisor to KAL flight operations. Probably a better agency if you are considering KAL; not if you have high ethics. Generally better T & Cs than Rishworth.
Rishworth - a lot of negative feedback. Some pilots complained of lack of care and communication once they have you in their pockets! Poorer $s and inferior T7Cs compared to GAP, EPA and CCL.