One factor of their success was they were experts in this investment niche:  They knew the buildings, their history, the budgets, the rules (rental caps), the board members, the sales comps, the number of rental units in the building, they bought in areas where there was strong rental demand and a good exit strategy of selling one day.  

I’m a commercial lender and my specialty is residential and multi-unit investment properties (it wasn’t my intention, but it’s become my niche).

What are some things to consider that may be unique to buying this type of rental?

Uri Rafaeli, who lost his property and all the equity associated with it, is just one of thousands of people to be victimized by Michigan's uniquely aggressive property tax statute.

Traditionally direct mail has a response rate of 1-3%, but in competitive markets it may be less than 1%.If you are going to do any DMM I recommend using very targeted niche lists and totally custom mail pieces as a way to stand out from the crowd.

We had a very unique, beautiful space in a small city downtown.

I've found a pretty good niche in the neighborhoods that are a little nicer with the better schools in Waterloo.

With the third space rented (ideal for a doctor/medical professional due to proximity to Holy Cross Hospital), this property has a potential for $8,800 - $9,000+ in monthly revenue.Situation - Because there are no recent comps nearby for a property in this unique category I have been unsuccessful in determining a solid ARV to allow me to work backwards.

@Dan Maletta Yes, I'm primarily interested in buy and hold for a few reasons: (1) This will be my first real foray into real estate investing and (2) I'm fully expecting to make a ton of mistakes as a rookie investor and I thought low income housing would be a safe place for me to learn as much as I can before I find out what my niche really is. 

The more rehabs you do, the more you start learning about contracts, estimating ARV, estimating rehab costs, you'll start putting together your own deals, you'll start looking at niches where you can find deals and learning how to market and negotiate to those niches.