My biggest concern is finding the right contractors.

Your biggest limitation is your knowledge of the market, which usually means I like investing near where you live.

My biggest issue is the number of out of state investors who operate these STRs.

You may want to read up on Chicago Tenants rights.Finally , it sounds like you  want the biggest bang for your buck.  

@Malik Batchelor I think the biggest thing would be to ensure that you are offering a good deal.

For me the biggest issue was the DTI calculation.

Airbnb managed the interactions between hosts and guests and one of the biggest risks for guests when booking through a platform like Airbnb is "Host Risk" As a traveler, are you going to be dealing with a crazy host or a professional?

In business the biggest PITA people you will ever deal with are "frugal" people and "rich" people.

I would imagine that it is quite a competition zone in that starting price range.I think the biggest block I have in my brain right now is the deal analysis and getting the numbers to work right.  

Therefore, be prepared to work and invest more time and money than you initially expect.Two biggest advice to shell out are know your numbers and all the auxiliary costs besides the obvious purchase and rehab.