There are many. We've worked with five or six. It really comes down to the property you want. A good place to search owner listings is https://stjohn-villarentals.com/ - you'll save 5%-15% going direct. Personally, I have used Caribbeanvilla.com (extra 5% service charge), destinationstjohn.com, cateredto.com, carefreegetaways.com, cloud9villas.com... I have no loyalty and look for a great property.

Cheers, RickG