Lighter, better fuel economy, and "less" maintenance. The first two are pretty much a given, the last one is yet to be seen. It's all about the bottom line, whatever can move the most people from point A to point B for less cost to the airline.

As for the PW1000 NEOs, it seems like a great concept but as with anything new it has its growing pains. It may become the new standard design since standard turbojet engine efficiency is already highly engineered to the limits of modern improvement.