Thoughts Around Multiple Mortgages

[Grant L Cohen]

All, curious to know your thoughts on having multiple mortgages for rental properties. I currently live in a three level condo building (each floor is a separate owner) and I have the second floor unit with a mortgage. I have a nice relationship with the owner upstairs and she would like to sell sometime next year in 2020, likely beginning of Q2. I have already been in touch with a bank on specifics, downpayment, closing costs, etc. Curious to know about additional areas: 

1) What should I know about having multiple mortgages? 

2) Is there any tax benefit to owning 2/3 units in the same building?

3) Any horror stories? 

4) Other?