Very happy with our NP45 as well. We're still in the shakedown phase, knocking out some bugs. But we've got around 80 hours of very comfortable cruising now. Some high-level differences from when we were searching.
1. The NP is not really a Blue Water boat. Out of the gate, it's not going to have the same level of redundancy and all-around toughness of the Nordhaven. Even after upgrades, the Nordhaven's are just built for the ocean. However, that creates some tradeoffs. The NP, however, is great for very comfortable coastal cruising.
2. The NP will have a much larger salon than the Selene, since it's full-beam.
3. The fit and finish of the Selenes is very nice, but in recent years the NPs are catching up. In an older model, the Selene will feel more luxurious.