RevivalRO is most up to date server I've played on (14.3 atm and working on it). It has new instances such as Bios Island or Sara Memory as well as most kRO items. The community is still very small but really kind and the GM is most helpful staff member! She solves problems right away. This server has been opened not so long ago, so there's aren't many people here yet but we can see how the number of players keeps increasing. For hat lovers they have hat disguiser NPC, which is most useful.