We are doing our 18th charter this fall. Only once have we used a charter broker, and that was with
Tahiti Yacht Charters, and only because the owner (a local) turned us over to Poseidon, who is their North American agent. We had zero problems with the charter company, and with the agent.
Go online, try Trip Advisor, and do some searches on Dream Yacht. When someone posts a problem, the response from DYC is "you chartered through a broker, you need to take it up with them". As I've noted, we have done 17 charters. By far, worst ever was with Dream Yacht. Do a search in here, you will find the threads.
Travel
insurance doesn't help when the charter company tells you that you are getting a 4 double
cabin boat, and you aren't. Insurance doesn't help you when the
boat is less than a year old but falling apart. Insurance doesn't help you when the charter company promises you something, and then doesn't deliver. Insurance doesn't help when you lose a day or 2 due to
maintenance issues. Get my point?
Finally: When you charter with a broker, the charter company pays the broker. It doesn't cost you any
money. But, when there is a problem, is the charter company more likely to help when you chartered directly? I think so.