For xp'ng solo I think that Albion's Necromancer does very well. There are new servers that are going to open up at the beginning of July so you may want to check those out. They are no ToA servers. Otherwise I'm not really sure what server is best to play on. There is clustering, so starting on one will let you play with others from another server.
With the Catacombs expansion pack it's easy to xp with just about any class. There are taskmasters that give you XP quests to be completed in an instanced dungeon. There are also a good amount of quests in Catacombs that give really good xp.
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For xp'ng solo I think that Albion's Necromancer does very well. There are new servers that are going to open up at the beginning of July so you may want to check those out. They are no ToA servers. Otherwise I'm not really sure what server is best to play on. There is clustering, so starting on one will let you play with others from another server.
With the Catacombs expansion pack it's easy to xp with just about any class. There are taskmasters that give you XP quests to be completed in an instanced dungeon. There are also a good amount of quests in Catacombs that give really good xp.