Do you calculate your numbers?
How much is down payment?& how much is monthly payment? What is the cost to pay for the monthly payment, utilities, repairs and vacancy rate. How long you are going to keep it? Can you break it even?
Do you need any tax advantage? or do you need to positive cash flow to support your life style?
I will keep under 4 units to begin with. To buy a single family home as a investment is very good idea because there are a lot of bank own properties are there. It is easy to rent and it will appreciate also.
If you are buying real estate strickly as an investment, I would buy out of state. You're not going to get any reasonable return and your down payment will need to be huge. What will be the opportunity costs of the down payment needed to buy a small apartment complex?. If you are buying to live in and then sell in a few years (hoping that appreciation kicks in and take advantage of the 250/500k tax benefits) then I would look to a single family home or condo/townhome in teh best area you can comfortably afford.
Why are you looking into real estate as an investment? What other types of investments do you have in your portfolio? Have you discussed this with your tax advisor (they should be heavily involved in helping you determine what is the best investment vehicle given your situation). If you need specific help regarding properties, the real estate world can help. However, if you need help in determining the best type of investment, I would speak with your trusted tax advisor.