The best way to truly answer your question is to enlist the help of an REALTOR to give you the necessary comparables to perform your due diligence. With proper assistance and guidance, you'll be able to make the best, educated decision.
You'll need to consider many different factors. 1. Are you looking to buy and flip immediately? If so, you'll want to take strong consideration in a CMA to gauge your potential return. 2. Are you looking to purchase, make necessary repairs and/or renovations, fill vacancies and then sell? [If you have the time to address any vacancies, this will assist you in making more of a return on your investment as well as offering potential buyers a lower risk, especially if your multi family/unit homes are 100% occupied. If you plan to go with #2,' you'll need to not only obtain a CMA for market value - as well as review the area rental rates, vacancies, average days on market and look into how you plan to lease out any vacant units.
Back to my initial statement, the best way to proceed with your possible endeavor is to hire a REALTOR to help you make the most educated decision.
I hope this helps.
Century 21 Diversified