fist and meteor are completely different, fist is if you play like a voker/taank and you play close to the monsters, meteor if you rather staying away from the mob.
In terms of dps fist is better (isn't it?) because 1 minute of cooldown is too long!
I really like the animation of meteor but I have to admit that I get often canceled.
of course if you plan to do myth, you MUST get fist and not meteor, using meteor in myth would be suicide.
btw everyone has to do his own choice, as you already have rb fist, taking rb meteor
[[sorry If I said something of wrong... I'm still a noob... =P]]