I like Thomas Walker and Christine Wade's Nicaragua: Living in the Shadow of the Eagle, 5th Edition (2011). It is clearly sympathetic to the revolution, but takes pains to remain even handed. That means having no illusions, for example, about the political direction Daniel Ortega has been taking while also praising successful policies he implemented in the 1980s. I highly recommend it as an excellent political history. I would be tempted to use it in a class, but I don't tend to go that far in depth in a country study to merit an entire book.
The first half of the book is historical chronology, and the second half is separated by different issues: economic, cultural, political, and international. Nicaragua has a fascinating history, and the writing is very good. Who can resist sentences like the following?
On September 20, a young poet named Rigoberto López Pérez infiltrated a reception honoring the dictator and pumped five bullets point-blank into Somoza's corpulent hulk (p. 28).
My only complaint, and a relatively minor one, is that the facts can really stand for themselves in Nicaragua so there were far too many uses of the words "alleged" and "apparently," usually referring to some nefarious connection to the United States. But there were so many such nefarious connections that including rumors weakens the overall argument.
I agree with their assessment of Ortega: "The Ortega government was both openly defiant and curiously submissive to the demands of its old enemy" (p. 213). The more things change, the more they stay the same.