Where to stay in Los Cabos?

My boss is taking a female friend to Los Cabos. It is his first time. He and his companion are in their late 40's. They would like a classy, peaceful, upscale hotel. Should they stay in Cabo San Lucas, San Jose del Cabo or the Corridor. He wants to go to the beach, dine at upscale restaurants and sightsee. Where do you suggest he and his guest stay? Thank you.