Low reps suck IMO unless your using small rest periods. Ive come up with the idea that you should only do them for 2 or 3 weeks to break a plateau.
Do 15-6 reps 1-2 minute rests(2 minutes for compounds and 1 minute for isolations) moderate volume for hypertrophy
Then when you plateau
Do 8-1 reps 3-4 minute rests small volume for strength/power
Then go back to hypertrophy
Then take a break