BCAA are not essential to the average trainer with a high protein intake. But if I was competing......and when I am on cycle and doing intense grueling workouts, I consider them an important supplement.
The only time you need BCAA supplementation is prior to and throughout your workout. The Branch Chain Amino Acids Leucine, Isoleucine, and Valine are the aminos most quickly depleted during an intense workout, and the body will cannibalize lean tissue to obtain them. No type of protein, liver tabs, whey, or anything else will deliver enough of these 3 aminos with the speed and efficiency necessary to prevent catabolism. I like Beverly's MUSCLE MASS BCAA's, and they are expensive. I take about 4 before a workout, and 4 tabs every 10 minutes during my workout for a total of 28-32. I notice a marked decrease in soreness the following day. (Haven't been training heavy enough lately to warrant the high cost)
If you are competing, taking BCAA is cheap insurance against catabolism and just one more edge on your competition.
ICE is another very effective BCAA product and is more reasonably priced as well.