Well, I never said it was infallible! and, BTW, I am NOT a Schweser employee and am not giving sales pitches, just commenting on what’s available and on my own experience. Now if you want to talk about errata, I have never seen so many errata as in the Stalla materials…they were sending errata notices literally every other day and I found it was an enormous time sink just to try to follow all their links to correct their material!! Peter Olinto is great but you have to turn the volume down, 'cause he shouts EVERYTHING…at the end of a session my ears hurt!