That ended when I bought their "Creating Applications with Mozilla" book (http://shop.oreilly.com/product/9780596000523.do), which was riddled with misprints and errors, to the point that even the "Hello World" example code at the start of the book didn't work. It was disgracefully bad. I was actually, literally shocked by how bad it was.
That was 11 years ago. And I haven't run into a whole lot of "buy the O'Reilly book" recommendations since.