Cosmic Orb vs Arc

Just like te title says, I am wondering if anyone has a solid idea which is better? I know arc does more damage, but less hits I believe, but in pv I noticed cosmic does more damage per tic than arc does. Any thoughts or ideas would be helpful, right now I am using an arc ragnarok. Can add pics if necessary. Thanks guys.

if pvp cosmicorb is better all the way and u can inc its duration by adding living force (also inc dmg when it returns) it is also good in pve for aoe dmg since it can hit lots of mobs in the area.
arc is quite good in pve (workwell w/ whirlwind warrior if u want to hit mobs ahead of you) ex. ur ice build and u want to freeze mobs b4 u can reach them then arc is the choice it deals 600%mh dmg (though only 5 targets can be hit by arc)

if ur a rogue chakram pve i suggest use cosmic orb w/ living force or bombardment (since chakram lack aoe dmg unless u go proc build w/ diff skill) if u go proc build try cosmic orb+orb proc+throwsword proc+living force then just use twister or storm mh special for additional aoe/cc skil.
(just a suggestion though) also cosmic orb deals 300%mh dmg per bolt and living force inc duration of cosmic by 2-3sec atleast so it can easily out dps arc.