I would suggest that you check with the condominium property manager for starters. He/She can tell you who either markets (farms) the development or suggest one who does lots of sales in the development. The reason why you want that information is that those Real Estate Professionals know the development better than those who either do not farm or sell there. Those Professionals would have more knowledge of the rules and regulations and the approval process that your prospective tenant would need to go through. If the manager does not know, then ask the neighbors...they are always a wealth of information.
Finally, one last thought...after the manager (or the neighbors) gives you that information, interview those agents and select one that you think will work best with you.