I can't think of a good reason to use NetBSD [1] over Linux [2] for any architectures that Linux supports. I guess licensing is an issue for some companies. If there's another reason, the NetBSD project needs to communicate it better to attract new users.

[1] http://www.netbsd.org/ports/#ports-by-cpu

[2] https://en.wikipedia.org/wiki/List_of_Linux_supported_archit...