Have others used them and had a positive experience?

Start local and small, then grow from there with experience.

A minority of 401k providers will let you transfer the loan to a new provider, but I have yet to experience that option with any 401k I have had. 

Ask how many units they manage and how much experience they have.

It's pretty much why I'm putting myself out there on here, which to gain insight on other's experiences with working a dual agent deal.

In my experience as an agent (and long before an investor) people who are ROI driven and don't come with a passion for brick and mortar do not succeed in REI. 

@Nick HenryIt sounds like you want to gain experience to scale a portfolio over the 1-12k per year cash flow.

Would love to hear your experiences. 

It seems like you are either taking bad experiences that you have had, or things you have heard, and you are blanketly applying it to entire strategies that have worked and been helpful to tons of people. 

I'm interested in investing in rental properties around Columbia as well, I'd love to connect with fellow investors and/or agents with experience working with investors.