I defeated Grand Master Aki the other day. It was a rough fight, and I only won by the skin of my teeth. It was pretty nice to get three achieves all at once. And even better, the I Choose You Achieve gives you a heavy sack of gold. I was expecting maybe 500g, if that. However, that sack was actually heavy! There was three thousand gold in it!
My current goal with the pet battles is to defeat the Pandaren Spirit Tamers. The master tamer fights started getting more difficult towards the end of Outland, and once I got to Northrend I needed to make sure that I wasn't bringing a pet that was rock to the NPCs paper. However, once I reached the Cata tamers, and especially the Pandaria tamers I needed to bring a set of pets that was scissors to their paper.
So my progress against the master tamers slowed down quite a bit. It turns out that the pets I think are fun aren't necessarily the ones that can get the job done. I've had to go back and level a few different pets to fill holes in my pet family roster. Specifically the Dragon Kite, though awesome, is not a good flying pet at all. I had to level a parrot to replace it on my rotation. I also ended up needing to level a crab to replace my lovely Golden Civet.
Most recently I've leveled up a Protodrake whelp to fight the Darkmoon Tamer. So my rotation against him now is: Protodrake whelp, Phoenix Hatchling, and Clockwork Gnome. I'll restart the fight until I get the Darkmoon Eye first. The magic eye goes down fast against my Protodrake Whelp. And then I can handle the other two Darkmoon pets with my correct counter pet.
For a while I was entirely stuck against the master tamer in Krasarang. That wiley Hozen had a badass parrot on his team, and I didn't have any magical pet that could take it out. In fact all my magic family pets were green quality at best, which, when fighting against the purple quality pets that the master tamers have, is just not sufficient. I tried for a while to get a blue magic pet by slaughtering the Arcane Eyes that spawn in Deadwind Pass. I never did see a blue quality one of them, but eventually the game apparently felt sorry for me and one of the fights dropped a flawless magic battle stone. I immediately used it on Legs, and then went and tromped the Hozen's pets.
I also leveled up a hopling for it's humanoid attacks. The last master tamer in Pandaria has a dragonkin with some powerful mojo and I need a counter to it. I looked through my pets, but couldn't find an undead pet that could do some humanoid damage. Ah well, the hopling took out that dragonkin pretty handily. Now I'm considering what combos I need to beat the Pandaren Spirits. I haven't had time to do more than lose horribly to the earth spirit and his stuns.
Now that I have a bunch of pets at 25 I'm considering what I can field for a PvP pet team. I'm leveling up is the Mechanical Pandaren Dragonling so I try a PvP team with that, the Dragon Kite, and the Clockwork Gnome. I think that the lightning storm from my Kite will combine nicely with the mechanical attacks from the other two pets. I'm also looking to try a team with a Darkmoon Crow, Dark Whelpling, and some third pet I've not decided on yet. Something that can benefit from darkness, or that is anti-humanoid, maybe both if a handy battlepet exists!