NWP is a great mod for FC.
I have a few issues with using it & FC, however:
1) Nobody updates their user-created scenarios. Many that come with the mod aren't compatible and there doesn't seem to be hardly any coming out.
2) FC has a jerky graphics bug on WinXP. The XP fix helps a bit but it's still there so the ocean, rain, and the vessel you have hooked in the 3D window stutter constantly. Even after adjusting video effects.
3) While extra units were added, it's still not even close to the variety I'd prefer.
4) ASW: NWP improved ASW quite a bit, but I still feel like subhunting is too easy. It's just the way FC was made.
5) Along with other very minor annoyances that most games have - such as being a real pain trying to target missiles that are too close together. There's always ones I can't hook when seconds count.
I also own H3 3.6.3 and HCE (recent purchase). I'd definitely say HCE is my preferred medium now for numerous reasons. Interface, variety of many sorts, and relatively low on outright bugginess.