I agree that detailed analysis is very important as there are numerous factors (such as local demand, the cost of county approval, land prep, gravel cost, labor, etc.) to consider in determining if the ROI is ultimately worth it - especially since in our market, RV/boat spots command lower rent/square foot than a storage unit.  

What does Evolve do to command the highest fee in the industry?

The more you provide, the more attractive your unit can be, and the more rent you will be able to command.

We provide all of them and command better rent.

My mortgage is $534/month, I rent out the house to two soldiers so I get a premium on rent by renting by room (plus I'm in touch with their HR department on base for quicker tenant placement, and if they act a fool I have direct contact with their Commanding Officer - I am 100% not afraid to be a tattle tale on them!).

Good ones can command a higher price.

They are commanding higher prices than before because people are paying those kind of prices. 

All may offer some of the same financial benefits (owner financing, etc...) and, depending on your own reserves, may allow you to create the premier facility in the area that commands premium rants and can really be a cash cow.  

We are hoping to do a few more improvements before renting to help our chances of commanding the highest possible rent. 

That would help in determining the quality of the deal.Given my knowledge of Los Angeles and the areas that would command ~$1M for a duplex, your baseline rents seem on the lower end, especially if you are going to put in ~$25K in to each unit.