I have noticed that as companies they grow, their quality and attentiveness tend to decrease. 

As you already know, the quality of the investor agent will speed up your learning curve, and save you money, time, and headaches. 

I suspect most who requested cash for keys had previously received cash for keys.What I do instead is explain:- the housing shortage in my market and that an eviction will forever make it difficult to find a quality rental in this market. - I will ding their credit such that all credit cards and other debt will cost them more.- I will keep their security deposit for funds owed.- I will do my best to garnish future wages until their debt to me is paid in full.This has worked 100% time so far.  

@Melissa SejourRecommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.Property Class will typically dictate the Class of tenant you get, which greatly IMPACTS rental income stability and property maintenance/damage by tenants.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a property in Class D area to Class A standards, what quality of tenant will you get?

This is where you can significantly increase the value of the property by making improvements that attract quality tenants and justify a higher rental price.

and you will have many many applicants assuming the quality of the rental and the rents requested.  

@Cole Bossert I think @Sarah Kensinger and others have touched on the biggest qualities, especially communication.

The renovation aimed to modernize the property, enhance its appeal to potential tenants, and maximize its long-term value.

Perhaps a better vetting of the buyers on the BP side will enable better quality leads?

You also need UX, support, quality, a million other things.