There are two different types of wedding coordinators here in Playa/RM....the one's that work for the hotel/wedding venues and the independent wedding coordinators working directly for you, the Bride, their client.
A lot of times the AI/Hotel/Venue coordinators are hosting about 100 + weddings per year and have limited time to dedicate to one single Bride, so sometimes the personal attention, that every bride deserves, is lost with them. This is not always the case, of course - some are excellent! But there is always a chance they will no longer be in that position when your wedding dates comes around because they are working for a hotel and could either quit or get moved position.
For the independent coordinators, the best idea is to find someone that is compatible with you. Do research to see who is in the area and if you find someone that you like their style and presentation then try to schedule a phone call. Usually, you can just feel it - if its right you'll click. Are you looking for someone with set wedding packages or someone who is able to cater to you and what you are looking for? Do you want to be very hands on or hands off? Ask for references too!!!
For fee issues, you can always ask clearly their payment policies - there are many different ways to charge for coordination services.
Hope this helps!!