To get the best deal on your new mortgage, I highly recommend that you shop around to like 3 different places. Typically, the banks like Chase, Wells Fargo, B of A are what's considered A-paper lenders and they only lend to people with 700 credit or better. In my personal experiences, the banks usually has one of the lowest rates for borrowers with great credit and also the closing costs are usually much less than going through a middleman (Broker). Brokers can usually get you higher loan amounts than the large A-paper lenders like Chase. The interest rate typically a little higher when you go through a broker. Not substantial difference but definitely higher and the closing costs seems to be more than going straight to a local bank.
Get a quote from at least 3 different places and ask for a GFE. Good Faith Estimates is something that every lender is going to ask for to compare the cost of their competitors. Every bank or broker should provide you with a copy of the GFE so that you can see what your closing costs will be like at the time of closing.
What you don't want to do is go and try to get quotes from 10-20 different places since every one of those places will run your credit at one point and having your credit ran that many times in short period of time will drive your score down so it's not recommended that you just let loose and let every single brokers run your credit while trying to shop around.
I hope this was helpful to you and good luck with your search.