The nice thing about ACID is that the definition, when implemented properly, has only one meaning. But now that vendors are offering tunable CAP they are inserting a whole new level of complexity. What was originally sold as a NoSQL=NoDBA model is even more wrong than it was initially.
Tunable CAP, if implemented correctly and consistently, means that someone needs to be sensitive to the client, the business, and the developers. None of which the freshman programmer is going to be sensitive to on the first day.