(Several people I work with have recently asked me for reviewing advice, so I thought I'd share my thoughts more broadly.)
Peer review – organized scrutiny of scientific work prior to publication – is a critical part of our current scientific ecosystem. But I have heard many of the peer review horror studies out there and experienced some myself. The peer review ecosystem could be improved – better tracking and sharing of peer review, better credit assignment, more fair allocations of review requests, better online systems for editors and reviewers, to name a few.*
Should we have peer review at all? In my view, peer review is primarily a filter that limits the amount of truly terrible work that appears in reputable journals (e.g., society publications, high-ranked international outlets). Don't get me wrong: plenty of incorrect, irreproducible, and un-replicable science still appears in print! But there are certain minimal standards that peer review enforces – published work typically ends up conforming to the standards of its field, even if those standards themselves could be improved. Without peer review, more of this terrible work would appear and there would be even more limited cues for distinguishing the good from the bad.** To paraphrase, it's the worst solution to the problem of quality control in science – except for all the others!
So all in all I'm an advocate for peer review.