House Hack opportunity I am considering

[David Davis]

I am looking for my first RE investment property.  Was looking for multi family, but came across a duplex in my city where I would end up paying $400 per month for my "rent" ?  I live in Chicago so rents are fairly high.  The rental unit in the building goes for $2100.  The property has been rehabbed already.  It looks like a great deal based on the buy and hold analysis.  What else should I consider?  Am I missing anything?  I am a total rookie so all answers are welcome and nothing is "obvious" to me. 

Thanks