However, there is risk to the seller in that they no longer own the property, have to deal with the seller carry back note, would have to foreclose if there is a default by the buyer, and perhaps the biggest one is the gain is triggered and merely deferred and paid over a period of time. 

I have yet to purchase my own property but I'll definitely be pulling the trigger next year! 

Waiting to pull the trigger is fine as long as it’s not out of fear.

You can borrow with 10% down but that triggers PMI and a higher rate structure. 

So I finally pulled the trigger and purchased my first investment property in Trenton.

So look around and get some more perspectives before you pull the trigger!

Sometimes, a sale triggers full payback - so call your banker to confirm, but you are just basically offering seller financing and acting as an "intermediary". 

I can't tell you how many markets we've looked at and didn't pull the trigger on years ago and have kicked ourselves over it ever since (Boise, Denver, Nashville, Austin to name a few) as the appreciation would have been significant! 

@Christopher Mayer Everyones advice here has been pretty sound, you may want to consult the town about what it would take to get the attic unit to be a legal third unit, but keep in mind that changing a property from a 2-3 unit and the needed repairs will cost time and money and hurt your cashflow (property taxes will probably increase too) so re analyze the deal and make sure that the conversion makes fiscal sense before you pull the trigger.

I'm looking to see if I should pull the trigger on this one.