I really like pkgsrc. I'm not really qualified to give a technical justification for it. It just had the right simple, clean feel to it, which NetBSD in general has. I would even go so far as to say that it was fun to use.

I consequently once spent quite some time trying to get it working under Cygwin so I could use it at work, but never got past problems with Cygwin group names that have spaces in them. It was too complex for me to fix....