> So their "best practices" end up being questionable at 
  > best. Basically, who are you to claim that whatever 
  > you're doing is a "best practice"? It seems like a pretty 
  > bold claim, so I'd argue that it's not unreasonable to 
  > expect someone to back up their claims.

This is why IMHO the best advice comes with a list of pros and cons. It tells me that the author has thought deeply enough about the subject to understand not only the solution, but the contexts where the solution isn't a good fit. (Two books that spring to mind that do this: Patterns of Enterprise Applications by Fowler, and Design Patterns by Gemma et al.)