I just finished the mogu assault and I always get the lightning rod buff because its a nice damage increase. It usually hits for about 25k and can crit. Very nice as a tank because the mogu have 250-300k HP and this significantly reduces the time spent on the assault. But seems useless for ranged classes. Take the 25% haste buff from the pillar of storms at the whitepetal lake (42 41) with you aswell.
But you literally can take the buff with you. Into dungeons and raids. Tested that with the two in the vale. Buff remains upon entering. I know three minutes duration isnt much but if you can use it properly it has a significant impact especially on cleave fights.
Set your hearthstone to the vale or use the pandaria challenger port when the mogu assault is active and get ported back. Enjoy.