for me i find that i grow ( strength / size ) really well on a five day a week program.
the difference... low volume. ie 7 sets for chest, 5 for bis, 9 for back etc.
real short workouts.
i prefer a periodised system.
ill use the same weight for a few months (when ive reached a weight that im happy with ) . working to different rep schemes, 4-6, 6-8, 8-10, 10-12, 12-15(for legs,traps n 4 arms). sometimes to failure, sometimes not!!
oh and i primarily use machines. hammer strength machines though.