Elena,
The Acme School of Aeronautics (real school...honest!) pioneered the rote memory concept of passing FAA written exams. That works only as far as passing the written goes.
Unlike the CAA checkride....the FAA system has a very stiff oral exam prior to the flight check. Sheer memory will not survive that.
Unlike the CAA, during the oral exam you will be asked to draw diagrams of all the systems on the aircraft and be able to explain how the systems function in detail. Thus you will have to answer far more quesitons about systems than done on a technical exam in the UK.
The average oral exam takes about 3-4 hours if done correctly and the flight check will take about half that....depending upon overall performance. If one is found weak in any area of skills....then one can expect to perform as many tasks as it takes to satisfy the examiner of your competence or lack of.
The end result is the same....except under the CAA system one will have a treasure trove of trivia stored away that is wonderful fodder for discussion at the pub but does little for your real life flying. On the other hand, the FAA system tests your knowledge of what one needs to know to be to aviate safely and omits much of the trivia.
That is why it takes far longer to complete the CAA course.