The World Junior Championships aren't as prestigious as they once were, as the absolute top juniors nowadays are strong enough to play in events where they'll be paid quite handsomely for their appearance, and probably prefer to avoid the risk to their rating and reputation that such an event entails. Still, the tournament remains very strong and often interesting for those whose countries are well-represented in the event. (This is not the case for the U.S. this year.)
The girls' event is a runaway for the top seed, Aleksandra Goryachkina of Russian, who has 10.5/12 and has clinched the title with a round to go.
The boys'/open event is another story. Chinese prodigy Wei Yi led the field by half a point after 11 rounds, but after losing in the penultimate round he's part of a four-way tie for first with 9/12 with Lu Shanglei, Vladimir Fedoseev and Jan-Krzysztof Duda, and Kamil Dragun has 8.5 points.
There's a nice report on rounds 10 and 11, with a bit on round 12 as well, here.