Wot they said.
1. Ignore IPv6. Lots of stuff can't work with it yet, and it's another complication you don't need.
2. Avoid Homegroups. I had a nasty experience with one some years ago. It scrambled my computer and very nearly lost all my "stuff" - it locked all the hard drives it could find. Just use Workgroup.
3. It's exactly as Gertrude says: sometimes it just works, and sometimes it doesn't. I managed to network my Windows PC and laptop and a Linux PC that I used out in the "workshop". I think Mac is like Linux - you have to dabble with Samba and geekspeak stuff to set it up, but it does then work.