I ran S-4 after a buddy ( who competed in Beijing ) recommended them to me.....
physique didn't change much, strength went up a little, but the best part was the amazing stamina I had on it. I could do a 5 hour squat/deadlift day with my team and go home and mow the lawn like nothing ever happened that morning.
I ran .25mg a day every morning, and another .25 before lifting... upping this to .25 and .5 closer to a meet. .5 and .5 on meet day ( powerlifting)
The only side effect I noticed was a slight yellow tint to oncoming headlights at night... it was kind of nice actually.
I'm thinking of trying it on top of test for an upcoming meet, or as a bridge after the meet.