How to analyze a single family portfolio?

[Hunter Estess]

What is the best route to analyze a single family portfolio?  Income approach using a Cap rate?  Sales Comparison approach?

Situation:

A broker sent me a deal of 88 single family properties(~100,000 SF)all on the same street/neighborhood.  The asking price is 6.2M.  Fair Market Value in the area for a single family is $100/sf... thus valuing the properties at 10M...

If I analyze the property by using the CAP rate for the area(area CAP rate for Multi-family is 8%) then the property is valued at $5.3M....

Which should I use?