Pullovers are amazing for mass, they work the underlying muscles of the chest, and without proper development there the rest of the chest wont grow. They were a staple in many old body builder routines. Also if you have heard flies are useless than you must also know a smith machine is useless. DB flies have there place in a good chest routine, they allow for deep stretching and if only done with a limited range of motion, particularly the bottom half of the lift only, they add tremendous stimulation through time under tension. They get a bad rap because of pec deck machines and people who don't go deep enough with them. Cable flies are another great option if you have access to them because they allow tension throughout the whole ROM and force many stabilizers to come into play.
