I much prefer 8 knots myself as they are just more immediately visibly assessable. If it's wrong it 'looks' wrong right away as there is a clear pattern to the way it is constructed. The bowlines appearance is such that it is less visually intuitive - you'd have to give it a closer inspection to see anything wrong. As such I doubt I would ever use them myself, however friends of mine have recently adopted them so it seems sensible that I too should learn them simply for the sake of cross-checking. I myself have mis-tied an 8 once or twice while distracted, but then I'm the kind of person who sometimes goes to climb then realises they haven't put the harness on yet! Point is, we all make mistakes but group expertise and vigilance is essential for spotting them when they do occur.