The preface mentions the Shri Sai Satcharita and the Guru Charitra as two major biographies. Are any other similar works discussed, and what makes them distinct?

Yes, the preface in Chapter 0 does mention two other Guru biographies besides the famous Shri Sai Satcharita and Guru Charitra. One is a detailed and scholarly work written by Shri Samarth Sadguru Tembhe Swami, also known as Vasudevanand Saraswati Maharaj. However, this work is placed in a different category because it was written by the Guru himself, unlike the Satcharita which was written by a devotee. The other mentioned work is by Shri Samarth Sadguru Dattatreya Maharaj of Balekundri, but at the time of writing the preface, it had not yet been printed or published.