From the BM thread over at Elitist Jerks.

__Crit__
Almost all abilities crit for 200% damage, or 206% damage with a [insert meta].

__Mastery__
Mastery affects all damage done by our pet, including Kill Command. Mastery has undergone a slight change, as it is no longer visibly converted from rating to mastery to mastery effect, but jkust straight from mastery rating to effect. Behind the scenes, mastery is still coverted through both steps, and we need 600 mastery rating for 1 mastery. Each point of mastery (which we don't see) increases pet damage by 2%.

__Haste__
Haste affects both the speed of your shots (cobra and auto) and your rate of focus regeneration. You need 425 haste rating to get 1% haste. Haste effects generally scale multiplicatively. If you have 32% haste from gear and Rapid Fire, a base casting time of X would now be X/1.32/1.4. Procs that increase haste rating will stack additively with your total haste rating value (32% in this example). Focus regeneration is a base of 4 focus per second scaling multiplicatively with haste; i.e. 30% haste would be 4*1.3=5.2 fps. You will likely not see a huge increase in focus regen from upgrading gear.

Haste does have a non negligable effect on the smoothness of the rotation, and may be subjectively better than mastery or crit, even though simming hasn't shown it to be worth it.

Relative values

Despite what simulation tools say, haste is not a very attractive stat over what we cannot avoid from gear. "Faux reforging" over several valus of secondary stats between haste, crit and mastery show that;

- mastery and crit have a very high synergy
- haste and crit have an okay synergy, though not as good as the one between mastery and crit
- haste and mastery diminish eachother - in all cases it would be better to go either full haste or full mastery, with full mastery being significantly better within the observed min/max

In addition I also found that

- mastery and crit are very close together in value
- mastery will be better then crit at more intervals than vice versa
- a balance of mastery and crit shows better results than going purely for one or the other
- while haste may show slightly better results at specific increases, it also does so at specific decreases, and shows loss just before and just after these points - this can only be due to dead time or shot shifting.
- haste will, apart from the specific shot shifting points, be a loss over mastery or crit at all other tested points

This leads to a valuation of:

Agi>hit==exp (to cap)>>mastery>~crit>>haste