Construction - one story duplex or two 2-story townhouse?

[Weng L.]

I am buying a small vacant lot and looking to build a 1-story duplex (3br/2ba on each side) for rental, but due to lot size and trees, it will need to remove several trees to be able to build 1-story duplex. Alternative to removing trees, I can build two 2-story townhouses. 

From construction point of view, what are the pros and cons of 1-story duplex versus two 2-story townhouses?