EAS, MuscleTech, Pinnacle are the companies I personally avoid.
Depending on the product, diff supplement companies have different standards and purity rating.
example...
Metrx , Prolab = creatine, most pure 99% creapure brand, micro
Higher power, Egopharm = purest best qualtity prohormones
twinlab, biotest = best quality vs price ; zma
ect.....