I've only read three Marcus Borg books. I wasn't one of those people who needed to be convinced of a historical-critical reading of the New Testament, as I had been persuaded of that during my college education. In the mid-90's I read John Dominic Crossan's magisterial The Historical Jesus. Borg's books, at least the ones that people were often recommending to me, were written for a more popular audience than Crossan's more scholarly work.
I first read his Reading the Bible Again for the First Time, but it didn't tell me anything I hadn't learned already. Though I did like his way of wording things, particularly how he presented Ricouer's analysis of faith moving through phases that are pre-critical naivete, critical, and post-critical naivete. Borg located himself in the latter, so he wasn't a bomb-throwing reductionist or minimalist.
Which gets to his strength. He was an actual churchman who cared about his topics because he valued the church. Watching a video or interview with him, one was struck immediately by his generosity and grace. Brian McLaren has written a nice essay about his personal experience of Borg.
The book I liked best was The Meaning of Jesus co-authored by N. T. Wright. Wright accepts the same historical-critical method, but comes to different, more Orthodox conclusions about Jesus. This book stimulated me intellectually.
A few years ago I read The First Christmas, co-authored with Crossan. This book has been very helpful in preaching and teaching on the Christmas story. It does not bog down in questions of "did this really happen?" but explores the theological meanings of the birth stories recorded in the New Testament (including the story in the Book of Revelation that involves dragons and a war in heaven--the nativity story that most people overlook).
Christianity will miss this kind and gentle scholar, who cared for the church and it's people, and encouraged many to understand Jesus in ways they had not before. McLaren wrote the following:
Immediately after that panel, lines formed with people asking Diana, Marcus, and me to sign their books. My line, being the least popular, left me standing there somewhat awkwardly for long periods, but it also gave me the chance to eavesdrop on what people were saying to Marcus. Person after person said almost the same words, “If it weren’t for you, I wouldn’t be a Christian today ... I dropped out of church but came back after I read one of your books ... I’m still a Christian because of you ... I became a Christian because of your books.”
Their effusive comments brought me back to the Evangelical revival meetings of my childhood where people “testify” to how they were “saved,” how they once were blind but now see, how they saw the light and were born again. I remember thinking to myself, “Well, it turns out that Marcus Borg is an evangelist too, just in another way and to another community of people.”