It really depends on funding. I've been offered full funding for an interdisciplinary PhD program at the University of South Florida, and that program's faculty is extremely aligned with my research interests. But, they don't have a clinical master's, and I'd really like the ability to practice clinically/gain clinical skills in addition to my research. But if UCLA can't guarantee the same level of funding, then I'm not sure it would be worth it since the cost of living in LA is so high...
Congrats on getting an interview at USC! Do you have a preference between USC and UCLA? Are you applying to the combined master's/Phd program or do you already have your MSW?