I think people who are writing these reviews need to be educated as to why we dont yet have time clocks on the letter trains. Generally, off peak hours - MTAs schedule is correct for lettered trains except L and including 7 when in good service.
This app should update for Hudson Yards (was about to give a 4 rating for that but want to counterbalance all of the low ratings that are clueless as to the issues regarding subway time clocks) but for the most part its a good app. Forgot what I paid for it. Subway time does not have time tables for the lettered trains and this app does
Hershelp about NextStop - NYC Subway, v2.5.0