While the book generated a lot of useful and interesting discussion between us, we both felt and thought it was vague and not as in-depth as we were hoping for. We're grateful for it and think it will help things but is there anything better? We're looking for something that goes MUCH further into the details of strategies and psychological theories.

My personal criticism is that it was out of date with respect to neuroscientific progress (e.g. comparing it's explanations to the academic publications referenced in the wikipedia articles on BPD) which one couldn't fault it for but nevertheless, if there's a book that covers those things in much more detail, that'd be a big plus for me.