I just somewhat accidentally tripped on an article about what I would call FSLN Evolution. You can find it here. It is titled "The Rise and Fall of FSLN" and was written two years ago by Alejandro Bendana.
II find it to be a well-written and objective look at what happened between 1979 and today including enough background to better understand what was being attempted and what happened. It deserves reading to understand but it could be characterized as pro-FSLN, anti-Ortega. But, again, this one-liner doesn't do justice to the analysis.