No 6. BCs with soft back packs are not for serious divers. A particular brand of BC has found favour with the majority of British club divers. The styles available are all substantial, bulky, and almost military in their approach to design. They are a good product. On a world scale, however, they have only a tiny share of the market.
Most divers now use BCs with soft backpacks simply because they take up less room in the travel bag.
It's different strokes for different folks. Myth No 7. Integrated weight systems are dangerous. In an emergency, positive buoyancy can be achieved by dropping the weightbelt. Divers who are trained to do this, will.