Using the loan officer or mortgage company your real-estate broker suggests can be both good and bad.
It can help you when the real-estate broker has a good working relationship with them, thus insuring that your loan will be watched step by step to make sure it's done in a timely matter.
Plus, your loan officer will usually be on his best behavior for fear of losing his referral source (real-estate broker).
It can hurt borrowers when professionals decide their commissions are worth more than your financial interest. When this happens it becomes all too easy for both parties to charge higher fees or give miss information just to get the deal closed.
Remember the relationship between the realtor and loan officer can be quite an advantage to you in terms of experience and speed at which a well connected realtor-loan officer team can get your loan done. Be sure to ask outside sources if you think something doesn't sound right.
It's illegal for mortgage brokers/loan officers to compensate the real-estate agent in anyway for your referral.
Fortunately with today's access to information it doesn't seem to be a factor so much in the service or fees you see, but more a way for the loan officers to get referrals.