I recently reviewed a story by Lucky Mann that during the review process I tried to edit, and sent five or six emails, mostly during each chapter as I found things to talk about. I suspect it wasn't a very good edit job, I have to leave the decision about the review to others, I am prejudiced. I haven't heard from the author. I suspect he isn't particularly impressed or pleased. Life goes on, it seemed to me the experiment was good for improving whatever skills I bring to both jobs.
As a more philosophical question, since I have the attention of both, can a Reviewer do a decent job as an editor or are different skills needed for each of the jobs?
And, if you agree to edit a story, should you review it?