Any piece that argues that there is a single correct/better way to do things, especially in the academic world, is going to be wrong. So, a piece that says that Articles are better than Books is going to be wrong. If we were all doing the same thing all the time, then perhaps one medium for the message would be ok. But it ain't because we do not do the same stuff.
Why is this significant? The reality that some departments require a book for tenure, some places care more about articles, some don't care about the quantity of output but the impact. There are some interesting folks who had only a couple of articles and got tenure because each piece was pretty field-shaping (Ruggie and Fearon, to name two). And rankings often focus on citations, which usually only catch articles.
I am a big believer not just in methodological pluralism but publication pluralism. Different kinds of questions require different sorts of methods to study them and often different kinds of publications to explain the argument and the findings. Indeed, it is hard to believe that anyone who has had an article reviewed would ever argue that articles are the only way to go since most reviews ask folks to do a lot of additional work that cannot possibly fit into 8k-12k words.
Recently, I had an article accepted (with David Auerswald) that addresses part of our book project--explaining the sources of caveats and comparing three cases. The book looks at some broader issues (not just caveats but other ways countries control their troops in Afghanistan), many more cases, takes seriously variation within the categories, whether being a member of NATO matters (since non-members also take part in the effort), and we can develop the implications much further. The point is that each serves a purpose.
Again, anyone saying that there is one way to do this stuff is an idiot.