On "Santana 3" the guitar work is fairly evenly split with Carlos usually soloing first. Along with "Welcome", "3" is my favorite Santana album. My favorite solo is from "Yours Is the Light" on "Welcome".
I'm glad people are commenting about Santana's blues influences. On his debut album it's very obvious that he had listened to a lot of Michael Bloomfield and he has mentioned repeatedly that Otis Rush is one of his guitar heroes.
In a radio interview someone asked Carlos why his guitar solos are so similar to one another, he replied "I want my mother to recognize me when they play me on the radio".