I initially believed that this model would incentivize them to manage investors’ properties in the most efficient and cost effective way.

Very efficient units with LED lighting throughout make energy bills very low!!

I can see your misfortune on that first property as the foundation for your ability to execute quickly and efficiently on your subsequent projects once you realized the value in doing so. 

Has anyone converted one of these to efficiency rentals?

Cons: This doesn't seem like an efficient way to scale the business and eventually, I will either have to quit my full time job or find a property manager.

@Dallas HaydenElectric induction cooks well, faster than gas, more efficient.

In other words, if you desire a 10% cap rate for an asset it may or may not be relevant because if the general market is willing to purchase at a 6% cap rate you will be outbid (assuming the market is efficient). 

I've done most of the work on all the properties myself, but am now trying to move away from that since my job has become much more demanding and my time much more limited.I'm looking forward to contributing to the forums where I can, although I'll be the first to admit that the way I've done things in the past probably haven't been the most efficient way to go about investing.

This is true for all aspects of REI, either DIY and risk a mistake, or pay someone else to do it more efficiently.

Go ahead, efficiency is the way of the future and they will save you good money.