In Finding Organic Church, Viola gets very specific and practical about organic church life. The book's subtitle explains well what the focus is: A Comprehensive Guide to Starting and Sustaining Authentic Christian Communities.
While Pagan Christianity deals with unbiblical modern church practices and Reimagining Church focuses on the biblical basis for what church life should be, Finding Organic Church lays out more of the nuts-and-bolts of both church planting and how the church should then function.
The aspect of this text that I found most beneficial was Viola's emphasis on the importance of the itinerant church planter. Quite honestly, I had not given this much thought before. Viola makes the case that almost all New Testament churches were founded by or at least connected with a church planter (Paul was obviously one of these). The church planter, according to Viola, is important because he has experience in organic church life and therefore knows how to help/direct in getting a new church started. Also, if the body of the new church looks to the church planter as an authority figure, this is not a significant problem because he will eventually move on, leaving the church to the leadership of the Holy Spirit.
If you are interested in church planting as it relates to organic fellowships, then this book will be helpful to you.