Working with a real estate agent for investment property

[Chase Freund]

What kind of expectations do investors have with real estate agents when using one to help them purchase an investment property? 

Vice versa what are the reasons that some investors prefer to not use one when buying investment property?

Personally I take pride in my ability to be available whenever an investor needs a second opinion on a deal and being the boots on the ground for my trusted investors. I can also help them find a loan quickly, contractors for rehab, and title companies for recently purchased properties. Where else do agents add value to the investor?