With my Controller/CFO background looked at our annual spending. 

A fixed-rate manager might let you retain control over the booking process while saving on commissions.If direct bookings are a primary goal, having someone motivated to push these (beyond the traditional channels) is crucial.

As a smaller investor, it's great to do all the data analysis with widely tracked metrics, but its also refreshing to hear the emotional and experiential data points from fellow investors as well.

Understanding borrower experienceRewards - being in first position you are in control of property in case of default.

To start, research local markets, and understand property taxes, rent control, and cash flow.

To answer your question, the advantage the GP has is control, and the ability to gain wealth from their equity position (hopefully not so much for asset management fees) by selling at a big gain.  

Learn how to control your personal finances.

If you really don't value your agent's ability and think you can do it better, it's likely best that you 1) interview more to find one that you do trust, 2) go through the listing agent, directly, if you're that comfortable with handling your side on your own, or 3) maybe get your license so you can control your side of negotiations with the proper tools needed (MLS access with agent info, showings, contracts, tax records, uploaded listing docs like surveys, disclosures, broker assistance for questions, etc.).

But it wasn't until a pivotal moment that I realized the importance of taking control of my financial future.

You have control over it but it will be a lot more work.