I have mixed opinions about O'Reilly books. I don't think their quality is low but as a rule I do think they don't hold their value as long compared to books from the other publishers you cite partly because they publish many books whose subjects are less mature and often likely to change significantly in just a few years.
These days whenever I'm tempted to buy an O'Reilly book that I don't immediately need, I think about the stack I already have that I never read anymore and then check the discount. In the past two years I haven't bought any book of theirs not discounted by at least 50%.
I think that's true of all technical books. Before I part with my hard earned money on some technical tome, I ask myself whether it's a classic (Knuth springs to mind, K&R C), or at least I'll get some value out of it for the next few years. Otherwise, there's tons of good online resources that don't require you to kill a tree.
These days whenever I'm tempted to buy an O'Reilly book that I don't immediately need, I think about the stack I already have that I never read anymore and then check the discount. In the past two years I haven't bought any book of theirs not discounted by at least 50%.