It's really Oregon, the next grouping of 4, and then everyone else with some dangerous teams thrown in. The only competitive games UO had were the Arizona schools weekend and vs. Oregon State, but the OSU game wasn't that competitive at the end.
Stanford needed 2 last second 3s vs Colorado to pull off the win the other day. UCLA also almost lost to Cal, Oregon State, and Colorado. Plus they did lose to USC and got throttled by Arizona. Oregon State has barely lost to UCLA (OT), Arizona (OT), and Stanford (3pt). The Stanford/UCLA/OSU/Arizona contingent are all very even teams IMO.
After that, ASU is the clear 6th team right now having lost to all of the teams ahead of them (splitting with Oregon schools) and beating all teams below them.
Colorado and USC are quite dangerous but fringe NCAA teams. USC has wins over Oregon State and UCLA, Colorado has come painfully close to beating Stanford twice and UCLA.
Beyond that the competition isn't very strong (Cal, Utah, Washington, Washington State).