Personally, I prefer local over everything else. Local is a good way to make things more realistic. For example, picture a large map. There are two packs, one camp is at one end and the other opposite to them. One pack is planning to attack the other, therefore chatting in their own respective camps keeps the secrecy (of course, this is arranged OOC, so it's not that secret. Maybe leaving the exact methods unknown.) As you all know, Local is literally the chats of those who are nearest to you. Just like real life, you can only hear those who are near you.
Group and Party is a combination of OOC and IC chats. Everything is omniscient, minimizing secrecy or wonder. Party chat, for me, is used for a group of four or less. Friends, casual chat or roleplay. A group, is for, well a group or a pack. A swell way to contact each other, for grouping up and what not. General within custom maps can be used the same way, as a form of announcement tool, as well. Groups can be purely cosmetic/placeholders (so you don't receive group requests, a group tag, or a rag-taggin' clan such as Modoru or Vicious and Delicious) and of course a family, which most of them are. It's a pack, pride, or gaggle after all!