As you all know, this is a well recognized exam from Cambridge University. It is an upper-intermediate level qualification that corresponds to a B2 level in the CEFR (Common European Framework of Reference for Languages).
Why take FCE and not any other exam?
If you are looking for an exam to certify your level in English but you do not want it for a specific purpose (e.g. applying for a specific university in a foreign country, etc), FCE is for you! It is accepted in many countries, both in universities and in companies.