First off you should know the difference between a Mortgage Lender vs a Mortgage Broker.
A Mortgage Lender is a company. They only get mortgages within their company. For example: Wells Forgo Mortgage, Ruoff Home Mortgage, and Union Saving Bank are Mortgage Lenders.
A Mortgage Broker is an individual person. A mortgage broker has multiple sources to get you the best interest rate or loan terms possible. This is a more personable experience. The broker will be dealing with you directly, but he will be handling all the haggling with the Mortgage Companies. Just beware that some brokers have deals made up with certain mortgage companies for a bigger profit. This could make a better deal for them instead of for you.
I personally do not have a preference as a realtor on if the buyer uses a Mortgage Lender or a Mortgage Broker. Who ever can offer the buyer the best deals is what it really comes down to. My advice is to shop around. Get advice and references from family members, friends, and online reviews. I would then go and meet the Leander(s) or Broker(s) for a personal interview in order to make the best educated decision. It is important to do as much research as possible before making a decision.