I've played a lot of Volibear games but I rarely jungle with him. Volibear in top lane is pretty brutal because he wins most trades and has a broken passive. However Voli Jungle seems to be FOTM and I don't understand why.
He has good ganks and utility in his fling, but his jungle clear speed is slow, he's not that great of a duelist, so why do people pick him over other junglers with good cc and utility? Ex. Jarvan
Volibear has the same ganking problems as Udyr, yet people are flocking to his jungle because they saw it on streams.
Volibear isn't super popular because of his ganks, it's because he is one of the best champs in the health stack meta. W does sick damage off of health scaling, and his passive is basically a Mundo ult.
League of Legends IGN: JOEYballsGOTTI http://i.imgur.com/bLa3Q.jpg
Voli pretty much relies on baiting to do well in top lane. In a pro world where they know their champ matchups and how much damage they can output, Voli doesn't do well top lane.
Speed boost flip is a great gank tool though, and Voli does some work in team fights. For those that want him in a team comp, jungle is the only really great place to put him in, but it's not as if he does poorly in the job.
Thanks for the responses guys. From what I've gathered, Volibear is being played by pros because of team composition and meta. For solo queue, Volibear is good, but I think there are a ton of better junglers out there.