my wife started picking up some of the new pets that drop in old raids on the auction house, i believe mainly because she liked how they looked. but she ran out of cash about the time she realized she was actually getting credit towards raiding with leashes. so she gave me a shopping list of what she still needed and sent off to pick up the remaining ones. the viscidus globule was the priciest, at 17k on our server (the others were running 5-10k). a few minutes later:
she thoroughly enjoyed her mr bigglesworth, and promptly leveled him to 25. i do find the idea of an undead pet that does beast and elemental damage to be interesting, from a mechanics standpoint.
for myself, i'll be doing it the old-fashioned way (in part because i now find myself with a lot less gold than i used to have). i've resumed working on weekly molten core runs with ratshag, as he pushes towards his 50th exalted reputation, so i figure i've got decent odds of getting the pets from there along the way (picked up a harbinger of flame last week). then the missus said she'd help me farm for the rest. i know they're all theoretically soloable now, but these things always go faster with a healer, and she's good company.