As F-Bird says, if you listen to guys that don't do any research they will rawdog Comp Cams all day long. In reality when Johnson and a couple other lifter mfg's quit making lifters for a while a chit load of cheap crappy Chinese lifters came across that were made of inferior material....hence wiped out lifters and accompanying cam lobes. Johnson is back in business but if F-Bird says use the GM lifters then use them, he is a man that knows of what he speaks.
You can also do a search function on this forum..."cam break in" or something of that nature and you'll get all kinds of info. Most very good and then some not very good.