[Jeffy]

I went with dedicated students, and by extension student leadership. Experienced mentors make great resources, but if kids are dedicated, and motivated (which can be done by their peers) they can find the answers to their questions.
I would take a group of 15 dedicated students with full access to the internet over 10 incredible engineers and 15 students who think it's a club.

A great example would be team 2345. I love those guys. They built a competitive robot with minimal resources out of a parents garage with only 11 kids.

And if you think it's resources, my example brings in team 1939. As far as I know, they have a cordless drill, a socket wrench set, and a hacksaw. Last year was the first time they missed elims at KC and they made up for it at their second regional as a finalist and #2 seed.