Best pet to buy from the Blizz Store?

[Quintessence]

I don't pet PVP, but I hear the Blossoming Ancient is a great tank/healing support pet.

Against trainers I make use of Lil' XT quite often. Heartbreak + Tympanic Tantrum can take large chunks out of the entire trainer's team.

The other two pets that I think are mentioned the most for pet battles are the Pandaren Monk and Guardian Cub.

[Ravnhawk]

The Monk is good but I use XT far more then any of the others. To be honest I've never even used the Blossoming ancient I just pull him out cuz he looks cool with the color changes, plus I like using a pet biscuit on him.

[Moonie1]

Lil' Ragnaros destroys any mech easily in PVE, not sure how he does in PVP.

[Rendigar]

Considering buying 1 or 2 from the store whilst they're on sale.
Any suggestions on which are the 'best' in terms of battles?
Or like.. which ones would be used more often. Thanks ♥

(PS: Already have Brew Pup & Cinder Kitten; Other than those 2)

Many will disagree with me, and they are absolutely entitled to their opinion, but they're wrong. (this is tongue-in-cheek, nobody get offended!!)

Lil' Ragnaros is the BEST pet you can get for one reason and one reason only. Go someplace wet, say the middle of the ocean. Pull out your little pal Raggy. Put on your chef's hat and apron. Whip out your rolling pin. Now cook up a few dozen feasts for your next guild raid. I'd like to see Lil' KT or that kick-@$% Pandaren Monk beat that!

I bought him the moment I found out he could be used as a cooking fire and I've not regretted it since. He's also not bad at fighting (having the highest attack power of any pet, IIRC, and being a conflag/flamethrower synergy).

[Rendigar]

Not even gonna lie, this cracked me up so bad. LOL.

I aim to please! No, actually I aim to hit. But that's beside the point. Glad you liked it! And I really do love my mobile cooking fire, especially when I pull out my legendary hammer so I can pose like him, or go smash his namesake in Molten Core while he watches (not crazy/brave enough to tackle firelands with a lvl 60 weapon though).

[Hermy]

Pandaren Monk is definitely a good choice - he's a very solid Humanoid!

[Graven]

More solid around the waist region.

[Azrile]

The two I see the most in pvp are lil rags and blossoming ancient, but neither of them are that bothersome. Lil Rags destroys mechanicals.. but so do most elementals.

As far as pve. pick the trainer you are having the most problem with, and choose that way. I use panda monk and lil rags vs some trainers.. but there are substitutes that are almost as good.

Sorry to not be so helpful, but my advice would be just go with the one you like best for appearance..

[Jabart]

Lil' Ragnaros is awesome, and probably a bit underrated. He has the highest attack in the game. The built in Conflagrate combo is also great.

Blossoming Ancient works well with in conjunction with other healing pets due to Sunlight, but as you mentioned, he's not on sale right now.

[Avalee]

Lil' Ragnaros is the store pet you see the most but I came across a Lil XT the other day and just totally massacred my team!

[Amuneta]

Along the lines of random usefulness Lil X.T. can be used in a pinch to smash some annoying trains you come across. I tend to use it for that more often then not.