First of all, the start itself is a little slower. In addition, before starting the engine it will give you a cooling time based on temperature and time since the last shutdown. Cold engine is zero, for warm engine I've seen anything from 10 seconds to a couple minutes depending on how much time between shutdown and startup. There is now an option to cool both engines simultaneously before starting the first one, saving a minute or two on the total start time.
All in all the start process for the NEO can be 3-4 minutes longer than a CEO. If you're doing the cooling during pushback and starting the second engine during taxi, the difference is less significant.