I was thinking about this on the can the other day... BTW, these are two of the best MU titles out there. Young Avengers is just smart stuff and the editors are really letting Heinburg cut loose by giving him full lease on characters like Kang and the Vision. I love this book. And Runaways is just pure fanboy goodness. Who didn't cheer when they saw Darkhawk and the gang at the end of Issue #2?! Awesomeness!
Back on topic, I think the Runaways take it by virtue of more experience as a team. Victor could funk up their teamwork a lil bit and lord knows, Molly and Chase could screw things up because they're so funny but the Young Avengers are serious rookies.
If the Young Avengers had more experience as a team, then I think Wiccan could effectively reverse Nico's spells. I still don't know how he's tied to Avenger's history but who knows, he might be a of a really powerful sorcerer lineage.