if you know market well, listing agent is the best way to go.

From my experience the listing agent especially powerful one can help you get the deal, sometimes loan can bid cash offer. After deal is done, we build up a few big brokers relationship in local. 

We always use listing agent, always get loan(75%-90%) to buy. It is my KISS investment secret weapon.

But you have to take care of yourself during processing. Don't blame me if you can't handle some trick part. It means you have to get your buyer agent. It depends on people's capability.