I grew on HST really well. If all you are looking for is growth, then it's great, provided you actually understand what you are doing and realize that HST is not a workout routine, but rather a set of principles that you apply to your workouts. A lot of people seem to think that HST is the sample routine provided on the site and that you must follow the whole 15/10/5 rep scheme, etc etc, which is wrong. The only thing you must do with HST is increased frequency over traditional programs, so that you are hitting each muscle at least thrice a week, progressively increasing the load, and taking an SD every so often.
I will admit, the strength gains were very paltry, especially compared to what I gained on 5 x 5. Still, I will likely continue to do an HST cycle a few times a year... the negatives really cause a lot of growth, in my experience. Heavy eccentric chinups are what caused my lats to blow up.
I saw a guy working on a DC/HST hybrid that looked pretty interesting...