"Was this just a clever marketing ploy?"
Nope. I got the book and it sucks.
I do agree with what seems to be Alex's core point - if you make performance clains, you've got to have figures to back it up. With .NET I'd personally like to see figures, IL and comparison to the alternatives (in both productivity and raw performance).
I'm with you all the way on this one Scott. I totally see Alex's core point, and while I can't validate whether they are true or not with respect to the book, I totally expect to see justification/explanations and so on about why something is best practice. I think this makes the content far more useful to readers...Do you want to learn strict best practices? Or do you want to understand how those decisions were made so you can properly adjust them for your given situation? Maybe the book does that, I don't know....