I wasn't actively looking to get this item, as I didn't think it would be all that great. I mean, considering the druid glyph, Glyph of Charm Woodland Creature, was bugged for the longest time (it might still be but I haven't checked), and Critter Bites is very limited in terms of flexibility, I didn't think much of yet another item/spell that would cause critters to follow you.
I was so wrong.
The item (not a trinket) has a very short cooldown (1 minute), and the critters that follow you will do so for 15 minutes. The panflute has quite a bit of range, and you can use the panflute on cooldown without despawning your current followers. I haven't found a limit on the number of followers you can have at any given time yet.
Yes, these are flying turtles and penguins! A guildmate who happened to be a mage suggested that I try getting flying critters to follow me, and as it turns out, those critters fly alongside you.
Then he had another brilliant idea: polymorph. Or more accurately, Crittermorph.
If you polymorph any critter prior to charming it with the panflute, they will retain the poly! This led to many moments of hilarity as I scouted all over for every flying critter I could find. The result is the screenshot above. XD
Since these are not true vanity pets, you can't use pet items on them like Magical Pet Biscuits. But I think that's appropriate; think of how obnoxious it would be to have 20+ gigantic sized flying critters following you lol!
For someone like me that was looking for a "pet leash" or something that would allow me to have many pets out at once, I think this a fairly good compromise. They may not be MY pets initially, but they're cute enough that I won't pass them up. :)
Edit: Apparently this is buggy for non-druids (flight-form works just fine as you can see above). Mounting up after using the panflute will cause the critter to freeze in place and it won't follow you. :( Sounds like the same bug that was happening with the druid glyph. Sadness!