I stayed in this unit for 9 weeks over the summer! There are some great parts and some not so good parts, but nothing bad enough to worry about.
The actual unit: the master is amazing (large and has great light). The second room is pretty cramped and dark. Everything in the unit is nice. There is limited cooking material. The shower takes a while to warm up and has okay water pressure. Big complaint: WIFI IS HORRIBLE.
The location: While this is in Spanish Harlem, not true northern harlem, I still wouldn't recommend the unit for anyone who would feel uncomfortable with homeless people outside 20 ft from your door 24/7, and tri-weekly police presence. All that being said, as a 22 year old male, I never felt unsafe, however, my girlfriend did occasionally. The metro is very close, and it is very convenient. I would take the 6 to 86th then transfer to the 4 to go to Grand Central for work (whole commute ~15 minutes). There is a grocery store across the corner which is cheap, and a laundry/dry cleaning service two blocks down.
The management company: Paul, the building manager, is great! Very attentive and easily reached. The company itself is okay. They were unwilling to make me a spare key set, and they didn't answer my requests that your wifi be fixed. They were vey nice about extending our stay, however which I greatly appreciated. Best part of the company is that they are very quick to respond when you want to rent which is a nice perk.
Overall, solid spot. The unit is great. The company is okay. The location is okay.