mortgage broker vs. portfolio lenders

[Diana Tian]

i see people here mention portfolio lenders a lot.  I wonder what is the benefit working with portfolio lenders directly vs. through a mortgage broker. I work with mortgage brokers from my agent's office. my credit score is low so 30 years fixed loan from Fannie mae would be too expensive for me 4.8 ~ 5.1%. my mortgage broker introduces me to portfolio lenders who often offer Arm products 4.25% 10/5 with 1 point up front. Would I get better rates if i work with portfolio lenders directly?