NYC Native makes some great points. When I was on the market to move from one JH apartment to a larger one, I was shocked by the range in prices.
Another thing to take into account is the monthly maintenance. I found that buildings with low maint often tended to have higher asking prices. That makes sense... your monthly payments (mortgage plus maint) might be the same if you are paying more mort and less maint. If the building itself does not have an outstanding mortgage, that makes the maint cheaper and the unit more valuable.
Also, buildings that have special stuff (amazing gardens, a parking spot, etc.) charge much more than similar buildings without those perks. If a building has a perk that is not important to you, you might want to skip that building, because you will be paying for it. Elevator buildings usually cost more than walk ups. A fireplace adds lots of value. Obviously, strong building financials are a plus, because you can assume that there won't be unexpected assessments.
There seem to be some buildings in JH, which, in my opinion, are just "famous" for no particular reason, and charge much much more for units that are not unlike units you could buy for a lot less a block or two away.
I also noticed that an extra bedroom was worth a whole lot more than square feet. For example, a 900 square foot junior four, that can easily be converted to a two bedroom, will sell for much more than a 900 square foot one bedroom, even if the two bedroom has boxy little rooms and the one bedroom is open and airy.
Also, location seems to play a big part in pricing. Once you get to the high 80's, prices seem to drop. In my opinion, that is where the good bargains are now. Also, with a few exceptions, apartments between 37th and Roosevelt seem to be a bit cheaper than apts a block north.
Ha! Who knew I would have so much to say about real estate. As I stated in a different thread, I looked at about 40 apartments before I found exactly what I wanted... and learned a whole lot along the way.
Good luck with your search.