Coop

And?

Noticed there is also a unit for rent in this building, just looking at different options.

Why do some consider this area borderline?

Not borderline; sea monsters.

It's not borderline, it's downright shitty.

Sea monsters and shitty?

The southern border for Washington Heights is at 155th street. Many brokers try to sell properties that are located in the 156-158th street area as Hamilton Heights, to try to justify a higher than market asking price, but it is simply untrue. There is a distinction between East and West of Broadway in Washington Heights. West of Broadway is safer, cleaner, quieter, etc. East of Broadway has been improving, but has a long way to go and is not going to change dramatically any time soon.

Is the area between 156-158th safe? I know things can happen anywhere but in general what's ur opinion semerun?

It depends on your comfort level. There is a much higher presence of open air drug dealing day and night in that section than if you went a few blocks south, below 155th street- also east of Broadway. West of Broadway is much safer. Your best bet to make a determination- attend the police community meetings of the 33rd precinct. The meeting info is at the bottom of their home page.
http://www.nyc.gov/html/nypd/html/precincts/precinct_033.shtml

The problem with west and south of Bway/155th is it's a bit of a hike when you want to score some drugs.

True, better to get a ground floor apartment at the Dakota.