I am dabbling in Aion, dual boxing a templar/cleric atm and am 18. Have no issues with 2-3 equal level mobs but not killing real quick unless I can dps with the cleric to.

Its very linear and I can only do short stints atm due mainly work.. Though I am told once you get past 20 it opens up a lot more so will continure on until after that and see how it goes.

I can see pvp being a total insanity streak to multibox.

Graphically its nice, macros are easy enough once you put a bit of work into it.

End of the day I am enjoying it mainly for a bit of difference from WoW & EQ2.