When Masteries were first expanded to skills other than Barding, i tested the hell out of it and posted the results. Some things have changed since then though. I really ought to compile a a new thread on it, with up to date info.
Skill Mastery Testing
Skill Mastery Testing Part 2
Just call me the "Master of Masteries", lol.
Taming Mastery is definitely powerful with real 120 Taming/120 Lore.
Lvl 1 gives "Empowerment", which converts Physical Damage taken into a DI/SDI buff for your pet, which makes them tankier and deal more damage.
Lvl 2 gives "Berserk", which allows your pet to store incoming damage for 6 seconds to raise it's Berserk level, the higher it's Berserk level the less damage it'll take and the more damage it'll dish out, but it'll also be resistant to healing (same effect as the Bestial Set gives). Once those 6 seconds are up, it has a 60 second cooldown before it can be used again. All in all, Berserk sucks, far too little uptime.
Lvl 3 gives "Consume Damage", which converts Physical Damage taken into a HCI/HPR buff for your pet (the HPR buff caps out at +30 now), and absorbs more Physical Damage than Empowerment does. This ability makes your pet
extremely tanky against Physical Damage, while landing hits more often.
Damage other than Physical, such as Fire/Cold/Poison/Energy, will bypass the damage absorb effects of Empowerment and Consume Damage.
All levels give "Whispering" and "As One".
"Whispering" will give your pet a chance to gain between 0.2-0.5 in a skill whenever it gains skill (up to 95% chance at 120 Taming/120 Lore) for 10 mins, and the cooldown is based on your Primer Lvl, with a 30 minute cooldown at Lvl 3, so 1/3 uptime.
"As One" can only be used when you have multiple pets out, and it evenly splits any damage taken between all of the pets. It's basically meant for hunting with a pack of creatures. There's two problems with this though. You can only heal 1-2 pets at a time (bandy one while casting G-Heal on another), and the ability hogs down Mana like there's no tomorrow. Definitely not sustainable.