I use NX because I have done so for years, it does all I need and basically, I can't be bothered to learn new skill sets.
It probably isn't much use if you shoot jpegs but if you shoot RAW NEFs then it is a natural choice. IMHO. Others will maintain that other software can produce better results and I won't argue but after trying them, I decided that NX was certainly good enough not to purchase and learn new software. Your needs, preferences and experiences may vary.