Would I recommend using them? I guess I never knew there was an alternative. I do not live in Jamaica, so I don't know that there was any choice for me. Flying to Jamaica for a marriage certificate would be a rather silly thing to do, IMHO.
That said, I can hardly express how irritating it was to work with the RGD. They seem to be staffed by people who don't want to:
answer the phone
take a message on the phone
return a phone call
do their jobs

However, I did confirm that they are certainly staffed by people willing to cash international money orders, as mine was cashed in very short order after arriving there. Had I not pursued the Ministry of Health to light a fire under Ms. Holness, I might still not have received my certificates.