There are only two servers: PvE and PvP, so it's really just up to your personal playstyle preference.
Here are some threads of other people playing Project99:
https://www.pantheonmmo.com/content/forums/topic/293/project-1999
https://www.pantheonmmo.com/content/forums/topic/2701/project-1999-worth-checking-out
https://www.pantheonmmo.com/content/forums/topic/3201/party-like-it-s-1999