Yes, the factbook is usually reliable.
(I bet they have a much larger version only accessible with a password)

I often turn to it for instance for the English names of countries and, in particular, of the inhabitants. My guesses in cases like 'Ivory Coast' are too often wrong.

But they have gaps. One example (just to remain in the area dealt with in this thread): They don't give a noun how to call the inhabitants of 'Gaza Strip'. In an old thread, I wrote that 'Gaza strippers' sounds good to me. More seriously, I'd call them Palestinians. The Factbook doesn't know that.

Wolfgang (asking himself whether the inhabitants of the Holy See are called Holy Seers, another deplorable gap in the factbook)