Amazon doesn't release numbers for how many people hold the different AWS certifications. They used to use sequential numbers on the certificates but they stopped that practice several years ago, so it's difficult to know how many people that hold the associate Solutions Architect certification have continued on to the professional level, but from some googling it appears to be only about one in eight.
Because of this, there's a lot more training available at the associate level, but here's what I've found that's available for the professional certification (let me know if the comments if you've got other training you'd recommend).
AWS offers two different training courses for the professional SA cert:
This course is offered as a free e-learning course via the AWS Training portal with 4 hours of videos with a number of sample questions with the different answers explained.
It's also offered as a one day classroom course by AWS training partners (either in person or virtual) that has the same outline, but presumably goes into the topics in a bit more depth. The course costs $450 (USD).
I took the free e-learning course and found the example questions and explanation of the answers useful, in particular in highlighting what's important and what's not in a question.
Building on concepts introduced in Architecting on AWS, this course covers how to build complex solutions which incorporate data services, governance, and security on AWS.
This class is offered by AWS training partners as a 3 day classroom course, costing $2025 (USD). I'm enrolled to take this course with ExitCertified starting on March 31st - I'm using the virtual classroom option. I'll review the training in a future post.
The training is expensive, but I'm hoping it will allow me to focus my preparation on the areas I'm weak in.
"A Cloud Guru" has a large range of Cloud courses, both focused on achieving certifications like this one and for specific topics. This course offers 12 hours of video, labs and practice tests. It's available as part of a subscription to ACG that can be bought month-to-month or annually. Unlike some of the other ACG courses, it doesn't appear that you can buy the course separately on Udemy.
I tried this course a year ago, and couldn't stick with it. The first section on Data Stores covered a lot of basic details that I was familiar with from the associate certifications.
This may well say more about me than the course - I don't really like video courses and I'm much happier to read a technical book or documentation where I can skim the content and focus on things that are new to me.
"Linux Academy" also offers a lot of online training. This course clocks in at 51 1/2 hours, but that appears to includes the estimated time for the labs and the 4 hour practice exam at the end - but that's still a lot of content.
This does appears to be a 2018 course and may be slightly outdated - the certification was refreshed in 2019. Like A Cloud Guru, you get access to the course as part of a subscription.
I haven't used Linux Academy, but someone recommended them to me. I'm sure like the A Cloud Guru course there's a lot of useful information here but that many hours of video fills me with dread.
Whizlabs offers a training course (9 hours of videos/labs) for $12.95 and a practice test with 400 questions for $29.95. Some of the topics appear to be very briefly covered (3 1/2 minutes for complex network configurations).
They offer a free practice test of 15 questions if you sign up, so I gave that a quick go.
I wasn't impressed with the questions as they didn't have the style of the sample questions I've seen, and some of the services asked about are unlikely to be covered in the exam - e.g. some very specific details about setting up AWS Managed Blockchain. I've seen this trend in other sets of practice questions available online, and I'm skeptical about how useful they are.
A quick Amazon search shows mostly books for the Associate certification, and a number of books offering sets of practice questions. There's also this rather strange self-assessment book that could possibly lead to madness if you actually tried to read it, based upon the pictures attached to the only review:
A complete waste of paper and ink. A jumble of words and phrases that have ZERO value.
DO NOT Purchase this book!!
At the end of the day, reading through the documentation for the services I'm less familiar with, and trying them out where possible, will probably be my focus after the training course I'm taking.
The AWS documentation for the separate services, combined with the FAQs tend to contain most of the information you need for the certifications. It's also worth checking out the whitepapers they have available for more high level architectural guidelines.