In addition, if i used fixed rate financing, my biggest expense is fixed.  

This is my smallest property but the biggest PIA to get lending on since I can't shop it to Fannie/Freddie and competitors.

The biggest indicator that they should not be comped against each other is from the market price of each.  

Biggest thing here is they wants a house big enough for 2 separate living areas and house cannot have more than just a few steps to entrance and hopefully rear entry/etc.

Your biggest variable is going to be prop tax, and it changes from street to street. 

The biggest thing you can do is build your CORE 4 which consists of getting a great realtor, contractor, property manger, and attorney wherever you choose to start investing.Let me know how I can help you get going

Biggest mistake I see is going to vacation and then half of the 45 day ID period days are gone or an investor looking for a (deal of the century and not being realistic).

The biggest downsides are that they usually have higher rates and require larger down payments.

Identify the biggest losses and cut those with as minimal a loss as you can.

Those are going to be my biggest questions when looking for something like this on or off the market.