Things have gotten a lot better over the past year with the NYC bike share, especially with maintenance, but there's still a ways to go.

Generally speaking, if you're commuting, bike docks (where you pick up and drop off) are empty when you want a bike and full when you want to return one.

The official Citibike app is also terrible, and the data Citibike makes available is often inaccurate (shows bikes or open slots when there aren't any). The app "Bike NYC" is a good (free) alternative, but obviously limited by data quality.