I have used it a lot. I like to do about 6 or 8 reps with the last one being the very last rep I can do in good form...then I put the weight down for 5-10 seconds and pick it up and try for another rep or two. I do this three times.
Dorian Yates used it a lot. Buy his book!
Be creful not to do it on all sets and in every workout because if you do you will over train. Use is once a week for a couple sets per body part.
You can get very good gains in muscle mass and strength using this technique.
I learned it from a VERY strong power lifting buddy of mine years ago. He would do lower reps most of the time but the concept is the same.
I used this before and during my contest prep. Put on definitely a few lbs of solid muscle. Plus love doing those types of sets. Will continue to train like that because #1 you dont have to do so many sets and you still train heavy and to failure. Makes me more motivated to train everyday!