I only really play minecraft factions (I personally co-own a 32 slot Factions server which we are in the process of converting into a tekkit Factions server)
But I think the friendly no griefing, seldom PVP spirit of the eGO minecraft server would be ruined with Factions as it is hard to differentiate between griefing and raiding (I know this from an admin perspective on my own server when this situation has come up)
So this leads me to believe that it just wouldn't work on the type of server that I think eGO likes to run..