If I had all the time and money in the world, then I would have sat a full ground school. However if you're short in either department, go for Bob Tait (as I did).
I wouldn't lose my confidence in Bob Tait just because there were a couple of questions in the exam which aren't in the textbook - Bob certainly did not write it as a test prep course (this is not the US-of-A).
As an aviator, we should try and read widely to expand our knowledge of aviation subjects. We want to keep learning as long as we fly.