Please disregard everything McMonarchist and ean521 said. they are VERY VERY wrong.
Starting your server as a network will kill it, 100%. your players, if you can get any to begin with will be spread out, the hub confuses them and it just doesnt work for beginning servers. I own a server that has 44 people on right now: Haven-Craft.com, also "multiverse" is not a real network server, thats all hosted on one box and very laggy.
You shouldnt take advice from the average PMCer in all honesty..
Factions and PvP are over made and very few people will want to join YOUR faction server over the hundreds of others with more players, id go with a completely original server and make an emphasis on the community. If you do choose prison or factions, you need to make them extremely unique make them different from any other prison/factions server you've ever been on.