Short and sweet, and hopefully in time for raiding tonight - here's Jaraxxus' loot table for cat and bear interest. Which is made doubly difficult with wowhead not actually, ya know, having the things. Note that I"m simply comparing against the non-heroic gear; heroic gear is going to blow all of this away.
Cuirass of Calamitous Fate/ Vest of Calamitous Fate(chest)- drops from 25-man Jaraxxus (#3 bear, #2 cat). This is a serviceable upgrade, and is better than anything in Ulduar for bears - but it's not as good as the crafted Knightbane carapace (higher hit) and not quite as good as the T9 piece. But the comparisons between it and the T9 are almost miniscule, so if you're wanting to spend your badges on something else (like you should) this isn't a bad thing to pick up if it drops. For cats, this is just barely worse than the T9 chest and is a very strong piece to get in the slot.
Pride of the Eredar/Pride of the Demon Lord (back) drops from 25-man Jaraxxus (#2 bear). The tribute pieces and the 258-piece is better than this, but with the high stamina and avoidance this is a great cloak. And there aren't any cloaks with high armor in this patch, so this is about as good as it gets for a while. Definitely pick this up if you can unless you've got the Titanskin cloak; with epic gems that beats this barely.
Charge of the Demon Lord/Charge of the Eredar (neck) - drops from 25-man Jaraxxus ( #5 cat) - this isn't even the best neck that drops so far; the Collar of Ceaseless Torment is better and drops from Icehowl. It's also not as good as Pendulum of Infinity if you've got that and barely beats Seed of Budding Carnage. Not a great thing to spend your DKP on, if you're going that route; save it for the rogues who want all that haste.
Planestalker Signet/Planestalker Band (ring) - drops from 10-man Jaraxxus (#5 cat) - now, in this case I do know a bit more about the rings out there, and this is excellent; the only things that beat it are the badge ring, the upgraded version of this and the one ring out of 25-man on hard mode difficulty (the normal mode doesn't beat it). The only reason you might skip it is if you're high on hit, but I'd still recommend it; hit, armor pen and good agi make this a great piece, and rings are hard to come by.
Endurance of the Infernal/Fortitude of the Infernal (neck) - drops from 10-man Jaraxxus (#7 bear) - while this isn't that bad, Boundless Ambition and Mark of the Unyielding both beat it fairly handily, much less the better items from earlier. This just doesn't have the armor, and that means it loses. I wouldn't bother with it unless you've really gotten unlucky with drops from before.
And...that's it! Nothing too exciting in my opinion; the best piece by far that you can grab that'll do you for a while is the cat ring and then the bear cloak. Good luck; it appears to largely be a tank&spank fight with a lot of healing and raid damage requirements.