I have Baby Blizzard Bear and I just got the reward beast from the new 5.2 pet battle dailies. I do have 1 flawless beast stone and I was thinking of using it on my Blizzard Bear but I would like some input before I do so. Other than that I just have a couple of snakes that don't seem too good but I'm all ears.
I am a Sweden native so my English may not be perfect. Please keep this in mind when reading my posts. I will try my best. Thanks
I'm a fan of the Feline Familiar. Prowl + Call Darkness will kill any dragon and will bring any other non-beast pet to near death (if it doesn't outright kill it). Though, in light of the FFF nerf, it would not surprise me if Blizzard nerfs Prowl + Call Darkness in a later patch.
For beast-stone purposes, I think Feline Familiar is by far the best option. If your primary goal is collection, Baby Blizzard Bear is a good choice, as is the Smolderweb Hatchling, Worg Pup, Silithid Hatchling and Baby Ape (the last two can only be captured in uncommon weather conditions, which makes catching a wild rare particularly difficult). For usefulness in PvE, most beasts with a high attack power will absolutely crush critters, although these can generally be obtained rare in the wild so there's no need to use a battle stone.