Report blatant self-plagiarism to journal editor or PubPeer? I came across an article by X and Y that is a nearly 100% self-plagiarised from an article by X several years earlier. A couple of words were changed,  but that is it. The figures and tables are the same and so is the list of references. The titles are different. The publishers of the two journals are different. 

To put it mildly, I am disappointed by the authors' unethical behavior, by the failure of referees to uncover the earlier work when reviewing relevant literature to assess novelty, and by the editor/publisher for apparently not bothering to use plagiarism detection software.    

My first reaction was that I should report this case to the journal editor. Based on what I've heard from colleagues, however, they appear to not always take self-plagiarism seriously, presumably because it's a lot of unpleasant work. Should I therefore report this to PubPeer instead? Or to the editor and PubPeer?
Taking the complaint public shames both the author and the journal, which may be counterproductive if the journal is responsible and willing to act promptly (mistakes do happen, even for very good journals).

I would thus recommend starting by reporting to the journal, which should have a procedure for dealing with such things.  If the journal does not take you seriously or refuses to act, then take it public and shame both the author and the journal.