^Don't think supplementing BCAAs have shown any benefit when they are adequately supplied in the diet. I've read though that they are useful if on an IF style diet and training fasted, in terms of reducing muscle catabolism and what not (Leucine particularly) and a lot of guys like Martin Berkhan and Layne Norton recommend this. Citrulline's supposed to be effective (esp. when taken with beta alanine) in terms of endurance as well as reducing muscle fatigue post workout, but tbh whatever effect they have is probablyyyyy simply not worth paying the money.
I only use creatine cause it's dirt cheap and lasts ages, and for the price has a reasonably impressive effect