I just read the book and whilst it doesnt have all the answers (will need the official report due out end of the year for that), you can see it was a good decision not to land straight away. It will be interesting to see what the report mentions on their calculated and actual approach speed and stall speed in their degraded configuration, as it seems like the margin was extremely low.
The book is a good read and there is plenty of praise for the rest of the crew, especially the FO. My hat off to all of them that day. The book does also mention in detail the 744 engine failure on his attempted dead head trip home.