Before you decide which agile certificate(s) to get, you need to ask yourself what you want them for. There are a number of different reasons for gaining certificated status in an area of agile, each with their own pros and cons.
First though, for those who have no idea what agile certificates are, let me explain. Agile is quite a broad field of knowledge these days, and there's lots to learn in lots of different areas. As a result of this, a number of different organisations started offering training courses in their specific areas, and when you complete these courses, or pass an exam at the end of the course, often you get a certificate of achievement, which helps to prove that you've studied what you've studied.
The slight problem is though that agile certification has in some ways become an industry itself, with so many different courses and certificates out there, it's can be hard to know which ones to get. Let's have a look at some of the reasons why you'd want to get a certificate.
The first is for the sense of achievement you get for yourself. Some of the exams you need to sit for some agile certificates can be pretty tough, so getting a certificate for passing can add to the sense of achievement, and keep you motivated to keep learning more. Given agile is all about learning and improving, if certificates are what keep you personally motivated to keep learning, then get whichever ones you'd find most interesting.
The second reason is to 'close the learning loop'. That is to say that sitting an exam at the end of a course makes you think through what you've just learned some more, and so helps to embed the learning even better in your brain. This is a great reason for getting a certificate, but it only really applies with some courses, and sometimes the exams at the end of a course are so easy that they don't help you learn very much at all.
The third reason is often the more common one, and is perhaps the reason you ended up reading this page. With so much money and so many jobs floating around the agile space at the moment, people get certificates because they think doing so will help them earn more and be more employable. Being honest, this reason doesn't apply anywhere near as much as it used to. Partly because so many people have got certificates now that the perceived value of many of them has decreased, and partly because so many certificates have come along that are so simple to collect.
Good agile people, and good agile recruiters, know the difference between the different certificates, and often collecting armfuls of them and putting them on your CV can make you look like someone who just collects certificates for the sake of it, rather than doing something equally if not more important - learning agile skills and competencies through direct experience in the workplace. As some people say, they value 'scars not certs', that is to say they'd rather employ someone with lots of experience gained through good times and bad times, than someone who's just spent time attending courses and passing exams.
Having said that, there are a number of certificates out there that require on the job experience in order to be gained. The Scrum Alliance's Certified Team Coach (CTC) and Certified Enterprise Coach (CEC) certifications both require lots of proven experience to be demonstrated before they are awarded, as does Scaled Agile Framework's SAFe Program Consultant Trainer (SPCT).
Everyone's experiences and opinions of agile certificates is different. The important thing to remember is that what counts at interview, and once you've got the job, is knowledge that you can actually use to add value to the situation you're in. Some people are motivated to gain that by attending courses and gaining certificates. Other people never get any certificates at all, and instead become great agile practitioners through direct experience. Most people seem to blend the two approaches.
The trick is to find the approach that works best for you, and use it to continously grow and develop your own skills and experience. That's probably the most reliable path to be a great agile practitioner, and reaping the rewards that can go with that.