In my experience, mortgae brokers are ok for people with little time to actually deal directly with the banks.
I have not met one yet who can actually get a better rate than the bank will offer me in person, the logistics gets messy when there is a middle man ie:broker , involved.
Dont believe all the marketing hype around the claims that brokers "research" the best deal for you, in fact they have a rating system within banks and certain brokers who do not send thru a quota of business to the banks are not dealt with by the banks.

Hence the first and foremost concern for any broker is to maximise trail, (commissions paid by banks for the life of your loan), so in a nutshell walk into the banks meet the loan managers, negotiate the best deal for yourself.