Not sure about that area, so can't comment about that.
Now, about having many units available for sale, that should be a concern ONLY if they are withing the same apartment complex.
Why? Because in a coop share holders have to carry with the monthly expenses for the entire building, not their individual apartments. The more empty units you have, the more stress that puts in the share holder's pockets.
Now, if you are talking about apatments for sale in different buildings, that shouldn't be too big of a concern. However, you should do a Google search for the statistics of that specific town: employment rate, crime, school systems, etc.
This website is a good start for that
