Well i've just started HST, so i can't yet tell you if it works or not. HST is 3 times a week and each session is a full-body workout, but you only do 1-2 sets per exercise each session, so you do as many sets as you normally would on a 3 or 4 day split, the only difference is that HST splits them over the course of 1 week. So if you were to go to the gym and do 12 sets all up for chest, HST is doing the same amount, just spread over an entire week, not just in a single session.
As for strength gains on HST, again too early to tell, but the main purpose of HST is for size, hence the name Hypertrophy Specific Training. From what i have read, some strength gains are expected, but again, the main goal for HST is size.