In good conditions, SFO to Levi's about 35 minutes. MRY to Levi is about 70 minutes.
Those are great redemption deals! While SFO is physically closer to Levi, I’d pick MRY over SFO for several reasons. MRY is about the size of my house (okay, a slight exaggeration), easy access into and out of, and you avoid the potential SFO weather delays. Plus, MRY has a great little restaurant onsite which is better than any lounge food at SFO.