Haste has two primary functions: it increases your white damage directly, and increases the likelihood that you will get an omen of clarity proc.

Crit has the chance to improve every single source of damage you have save rake, and improves your combo point generation.

In general, haste is better at higher gear levels because of superior armor pen (which helps the white attacks quite a bit) and because your OoC will do more damage potentially, especially if you are optimally using OoC. Crit is better at earlier levels due to the value of having smoother combo point generation and doing more damage easily without optimal management. Both are second-tier stats behind agility and armor pen, and are often considered worse than hit or expertise if you're below the cap.

Neither should be directly geared or enchanted for.

Plank, it's really dependent on the fight and statistical value more than anything. But just a quick note - you should make sure you understand that you're trading 710 armor pen not for 71% crit, but for whatever that 710 armor pen - agility would provide. The only place that most people give up agility for armor pen is on the trinkets and gems, meaning that you're probably talking about a 300-400 agility difference.

Now, where this can make a big difference is in the rotation; higher crit means more likely, smoother uptimes and higher FBs.

Crit isn't pointless after 60%. After 60% crit becomes less valuable because you will soon be overflowing in CPs and you won't get as much a benefit, but crit is going to be valuable until you hit the glancing cap, which is something like 75%.

Really, without understanding what you're comparing it's impossible to say. Are you talking about raid buffed? About practice on dummies? Are you talking a 10 man fight or 25? Which fight? It all really matters.

My excuses for being unclear.

With my 'tests' I was referring to Ignis and XT hardmode 25 man. 2 weeks on the trot I had tried with different set ups and dps was always around the same area. I am aware I am trading approx 400 Arp in gems and 80 in trinket for approx 400 agi in gems and 90 + 350 proc in trinket, but from what I had heard, passing the magic number of 250-ish passive arp and gemming for full arp would make a world of difference. But seemingly on the 2 bosses I had tested it was far less effective than AGI stack. I'm just at a loss as I'm positive Arp is the way to go .. but baffled as to why it is not working for me.

Thanks for a great summary. This is very helpful. I do have a couple minor corrections you may want to make to this sentence:

"Generally I hardly advice you to use RAWR or Toskk's DPSGearMethod. The value of every stat depends on the rest of your gear."

I believe that you meant to say "heartily" rather than "hardly." Also, advise is misspelled.

Boevis:
I do know better, at least in theory. As you've deduced, I've been in on some kills and gotten some gear. I'm mainly casting about slightly to eliminate possible reasons that my dps isn't landing where it likely should be, based on observed comments of other ferals here, various feral blogs, and even what Rawr is projecting me to come out with. First option was that there had been some evolution in the priorities we use for cat DPS, second was misgearing/mis-gemming/mis-enchanting, third was raid makeup/buffs, and fourth was simple failure to execute on my part/terribad.

So I'm not off on the DPS rotation and FbN's recommendations. I'm still Agi-gemmed since much of my cat gear is bear shared, and will be until I can truly separate them, but my gear is appropriate if not BiS. My raid configs are usually well set up, so I guess it comes down to execution on my part, noting that my keyboard agility is lacking and DPS often gives way to situational awareness, especially since I glance down at the keys and occasionally click my finishers like Rip.

So for example while I could excuse only 6400 dps on Hodir with "I was avoiding the constant icicles too much to live in spotlights, dead dps does no dps" I still wonder if I'm hitting the limits of my physical coordination and situational awareness. Ferals tend to top charts on a lot of Uld fights, but I can almost never catch the two rogues in my raid unless I have a good night on Vezax, and a fury warrior often tops me. I will at some point drop into the WWS thread, though the likely result is "dude you're terribad".

Anyway, to contribute usefully to the discussion, I agree with the clipping of Rip on cases like the brain and razorscale, the opposite direction is times like XT-002 just as he says "so tired" I usually try to cap my points and Savage Roar before the heart drops so I can burst as hard as possible early in the heart phase. Similarly the tentacles in the brain room provide quick combo points same way. Actually I do that on trash that's about to die too, who doesn't?

Cat notes in Ulduar, many of them I'm sure common knowledge:
1- Cat Feral Charge is almost tailor-made for getting into position on Yogg-Saron's Brain, I had too many headaches groping for good positioning for shreds, charge is perfect.
2- If using the "drag guardians to the door" method on Yogg, it's often not a good idea to Rip or the mob dies too fast.
3- I end up with a lot more mangles on Mim because he's constantly turning to face me, I mangle as I run through him.
4- Laser barrage is the best time to Berserk on Mim, the only time the bastard holds still
5- I prefer to Berserk while standing on a snowdrift right after Flash Freeze
6- On Freya I open the fight with hitting her with Rake a few times to get to 5CP as fast/cheaply as possible so I can start the add waves with a 5 point Roar up.
7- Auriaya I waver between continually single target dps-ing her (mangling since I'm at her feet) and working in swipe spam for the swarm adds. On the similar situation on Kologarn I stay single target.
8- For a feral cat, Vezax is Patchwerk reincarnated as a crayfish. My best night on him I think was 6100.

Are the dps values of 2xT9 and 4xT9 out there? Is 2xT8 + 2xT9 the way to go even considering ilvl258 T9?

Another question i want to ask since i'm in that situation now is: Was any study made already to determine which 2xT8 and 2xT9 items to take or if that is the case, which 4xT9 to take?

While the 2pT8 bonus is good it's not good enough to get past ilvl 245 items, much less 258. If you disagree, you can check out an analysis of what you lose least at the FBN thread.

A bit about this: the Yogg brain is confusing to get behind because each brain room seems to be in the same "place" for you as you go down, but they're actually arrayed around the brain at 120 degree intervals. This means that (because of the facing of the brain) you will always be able to shred if you run right up to the brain after Icecrown or Stormwind, but you will have to go behind the brain to shred on Wyrmrest (this is important if you used FC on a tentacle and it's not up to use on the brain).

You can just remember that the room that's the biggest pain in the ass (Wyrmrest) has the brain positioning that's the biggest pain in the ass (you have to run behind it).

Or, you could simply feral charge the brain, which will automatically put you in the correct position to spam shred.

Sadly I feral charge in then run around trying to find my shred point instead of just staying where the charge is, never quite realized kitty charge set us up behind target /failme

Just shred the brain from the south. Use your minimap. And you can save feral charge for more important work in the tentacle´s rooms.