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Nearly every sandbox MMO that is currently released and will be released is an open world deathmatch FPS full loot clone. The only good one of these that still offers tons of PvE content is EVE Online.
The only other ones that focus on PvE is Ryzom (and that is dead) and Anarchy Online (that is ancient)...SWG was good too, while that was running.
Runescape however focuses mostly on PvE. This is VERY rare for a sandbox game to do. This is almost unheard of in the sandbox world.
Along with that, the questing is actually good...it isn't go there and kill 10. But you actually have to quest, research, explore and what not...like a proper quest.
And the next update makes the game actually look rather good, especially for a java game.
So for those who prefer PvE...and like sandbox MMOs...Runescape is pretty much the only one out that does this, and will get a more modern look when it gets updated.