I just took the Solutions Architect Pro test. For those interested, here are my thoughts.
Aside from the SAP course, I also prepared by watching these other courses:
S3 Deep Dive – the entire course
Certified Advanced Networking Specialty – load balancers, and "Design and Implement AWS Networks" section.
DynamoDB Deep Dive – a few sections to help me with general understanding
AWS Certified Solutions Architect Associate SAA-C02 – it appears this course has been revamped. I would have watched everything but I didn’t have time. There are new services covered in the Associate course that appeared on the Professional test.
The practice exams are very helpful to me in that they help me prepare for the type and structure of the kinds of questions that will appear on the real test.