Two family condo vs. Two family home...

[Luis Rodriguez]

I currently own a two family home in an area where they have two family condos that are three levels. I've never heard of two family condo's until I moved here. There's a two family condo for sale for $740k. They had a open house recently and now have raised their price to $749k. These condos have 3 levels and the first floor seems to be rentable. I assume it's illegally. The HOA is $250. It's a 5BR,3 baths, yard, garage, and driveway.

We paid 749k for our house last year. It's a two family home, 6 BR's, 4.5 baths, finished basement, yard, garage, and driveway. What kind of appreciation am I looking at here ?

There's another two family property that the owner turned into a four family illegally. How does a property like that affect mine since it's still considered a two family ?