I'll probably ruffle some feathers, and on my first post here, but I'm going give an honest assessment, based on my experience with the CI process.
First, let me say that I would highly recommend finding an MCI (Master Casting Instructor) to mentor you. No matter how good a caster you are, they can teach you a lot. If possible, I'd recommend finding an MCI who has also completed the EDP (Examiner Development Pathway) process. Someone with the EDP background will be your best resource for being prepared for the exam. Can you pass the CI exam without a mentor? Yes, but it's tougher. Also, one caveat about mentors. If someone acts as your mentor, they are prohibited from being an Examiner for your exam. I mention this for anyone who might have a limited number of MCIs in their area.
Second, don't be in a hurry to take the CI exam. Take your time, and when you're sure that you can perform each and every task perfectly, which is where that MCI-EDP mentor will be an asset, then schedule your exam. You have 1 year, from the time that you officially begin the process, to pass the exam. Otherwise, you have to start over. I made the mistake of starting my CI process, by attending the workshop, and thinking that I would be ready within the year. I wasn't, but I had to take the exam anyway, and I failed. The exam is expensive, so don't waste your money by taking it before you're ready.
Third, get teaching experience. The focus of the exam is to see how good you are at teaching. I know someone, who is a very good caster, but failed the CI exam, because of his teaching skills. For example, I have been helping my mentor give casting clinics. While we're teaching casting, he's also observing my teaching, and gives me feedback/advice. He's also a resource if I have trouble conveying a concept.
Having said all of that, I've put the CI Exam on the back burner, until I see how things progress with the EDP. I think that the EDP is good, in theory, because it's supposed to ensure consistency in how the exam is administered. However, FFI might have misjudged some things, when they implemented the EDP. The EDP requires a significant commitment, in terms of time and money, and many MCIs have opted not to pursue it, which means that they will not be able to give examinations. As a result, there might be few, if any, MCIs in your region who can administer the CI exam. For example, there were zero CI examination opportunities, here in the Mid-Atlantic in 2017. In the past, candidates would have been able to take the exam at the Fly Fishing Show (Somerset, NJ), or the Fly Fishing Show (Lancaster, PA), or the Virginia Wine and Fly Fishing Festival (Richmond, VA). If I'd tried to take the CI exam in 2017, my best bet would have been to drive 8 hrs (round trip) to New York. I wrote a letter to FFI HQ about the problem, and participated in a call with HQ as part of the FFI Chesapeake Council, earlier this year. My impression, which was shared by other Council members, was that HQ didn't think there was a problem.
Only you can say whether the FFI's CI certification is worth while for you, but I hope the above helps. If you have any specific questions, I'd be happy to try to answer them.
Tight lines,
Dave