As per request on the other forum; let's discuss beta alanine.
The question first was something along the lines of Beta being useful in only high rep situations.
It certainly does help in high rep training, but not solely. Beta alanine works well in sports/athletics where there are high or consistantly high production of lactic acid. At this time, I believe, it is somewhat unclear as to exactly what mechanism the aid comes, but more research has been coming very rapidly.
Important to a strenght/power athlete, in a study done on football players supplementing with BA and Creatine, they lost body fat, 1RM Bench and Squat went up. It has the ability to increase work capacity at certain levels, which is where your going to get improvement.