Use SREmu, this is the best as i have been a member there for a while, they update often have a large team, its open source so if you have c++ skills you can change it and help them.
#This is quite advance the only problem is no npc interaction yet like buy items and get quests.
#There are no mobs already there on the server, you have to spawn them.
But this is the most advance one for Isro, but once the big update occurs which is Npc interaction it will be virtually done because this includes the 2 main aspects above