I’m preparing for CAE and use Masterclass as course book (I attend a prep course as well), so I can’t tell you anything about how good your coursebook is (and, of course, opinions are always subjective) - but though I can give you some advice which books might be good and useful for you.
Common Mistakes at FCE - great series and very useful!!! I bought all three - FCE/CAE/CPE - have a look at them and if you think they could help you buy the FCE one. They are small books and not too expensive, here each costs about 8 EUR.
Exam maximiser - it’s a combination of workbook and exam handbook - it’s from the Gold-series as your coursebook. I bought the advanced version and the CD (meanwhile there is an edition with a CD included) and in my opinion the exercises are quite helpful and very much orientated at the type of exercises in the actual exam.
Grammar in Use/vocabulary in use - I have “advanced grammar in use” and “vocabulary in use upper-intermediate/advanced” - quite good books for grammar revision and as a reference or, referring to “voc in use”, to widen your vocabulary. I think “grammar in use” is better than “advanced grammar in use” for FCE preperation purposes. “Phrasal verbs in use” could be helpful as well. The books provide exercises as well as clear explanations - look out that you buy the “with answers”-edition. The latest version is available with a CD-ROM, it is only about 2 or 3 EUR more than the without-CD-ROM-version so I’d recommend to buy the more expensive one and therefore have a nice CD-ROM as well.
“Focus On, First Certificate : Grammar Practice” - actually there’s a course book as well but I consider the practice book being more helpful. (I have the advanced one again).
And last but not least - the recent papers published by Cambridge - very useful to find out how good your knowledge really is and whether you are well-prepared for the exam.
There are probably several other books for the FCE - and among them surely several good books - but those above are my favourite ones. Which doesn’t mean that they are helpful for you too - I’d strongly recommend to visit a library or a bookshop and have a look in as many books/workbooks/references as possible to find out what you like.
And a few general tips - read as much as you can, books, articles on the internet… the same with writing, listening and speaking of course (the internet provides great possibilites, look for some friends you can talk to via Skype for example). Read various articles and don’t specify on “one” kind of texts. Find out a good way to record new vocabulary. And have a regular look (daily) at flo-joe.co.uk - especially at the wordbench.
Moreover have a look at the Cambridge exam website, they provide sample papers (if I remember right there’s a search box on the right, just put in “sample” and you should find them).
About the importance of having that certificate - I think the value differs in all European countries.
I hope this is helpful for you,
good look for your exam and have fun preparing for it!
Oh, and by the way - it’s “FCE” and not “FEC”!