I owe you all the reputation gear guide I promised weeks ago, and so, here it is. Never let it be said that I completely procrastinate on stuff I said I would do for weeks on end. I mean, it's true but you don't have to say it. The various quartermasters for the factions can be found here, if you're trying to figure out where to spend your precious points. They are precious, aren't they? Much like your torso. While there's ilevel 458 justice point gear, I'm going to be focusing on the epics, as those will last you longer overall. By the time you earn enough JP's to buy anything, you often have better gear from the dungeons you're running anyway.
Each faction has different items - some helms, others bracers, etc - and so, ultimately, it's most rewarding to work on Golden Lotus first in order to unlock the August Celestials and Shado-Pan, since that will get you access to the most items. The Klaxxi are a good faction to work alongside the Golden Lotus until you get the Shado-Pan and August Celestials unlocked, since you'll probably unlock revered with them before you finish getting Golden Lotus to revered, and can then focus on Shado-Pan and August Celestials. We'll cover Golden Lotus and Klaxxi rewards first, since you'll have access to them first, and then the other two.
It should be pointed out that if you are raiding 10 or 25 man normal Mogu'shan Vaults, you may already have access to gear on par with these rewards. That's intentional - Blizzard wants raiders to gear up from raiding, with valor points more serving the role of consolation prize if you just can't get that drop you need. But if you primarily run heroic dungeons or LFR, then these reputation rewards will be upgrades.