SOHC or DOHC

yo wassup, i've always been reading about dohc's is always better than sohc's, but no one has given a really good reason... let's see... d16z6, d16y8, d15b, vs. b16a, b18b, b18c's im more on the SOHC side because i seen some running way faster than b16's here... whats you opinion