A good duplex can provide you with private yard, an attached garage, and more of a "house" feeling but renting out the other half can dramatically reduce your expenses and possibly even allow you to live there for free.

That dramatically reduced the humidity in the basement.

Secondly, he mentions that he does forced appreciation on those deals in year 1 to boost the value of the house by 10%. 

Yes, that 3.5% down payment is amazing, but if you can boost it up to 5% and get a conventional mortgage, then you get to do away with PMI after proving you have 20% equity (I believe some mortgage lenders require 25% equity to dump PMI). 

It may open their eyes to more properties for sale that would boost that ROI. 

I don't expect a boost in rent but I know for re sale it will be a plus.  

If you upgrade the exterior dramatically, the building may end up standing out and looking odd / not fitting in...

We're about to start buying small multi-family rentals, preferably those that need some rehab to boost rents. 

In just 20-30 minutes per day, you can get moving, get those creative juices flowing, improve your circulation, and boost your energy.

The reason I ask a while ago I think I heard something about being able to "bundle" your properties together to reduce the price of utilities dramatically.