I have passed the Professional exam yesterday with 84%.
Advise for those who are preparing :
This exam will not just test your knowledge of AWS. Its more focused towards practical implementation of different AWS services and how they fit together to solve a given business problem. So, do not rush for this exam if you do not have some experience working/building solutions with AWS. First, it will be very tough for you to pick the right answer if you have not used the AWS services enough to understand their suitable use cases. Second, you will not gain much even if you clear the exam without having the actual practical knowledge, as in order to be qualified to be a true 'professional' on AWS, you much have some hands on experience of real life implementation.
Having said that - for those who are preparing for the exam :
My preparation included -
Linux Academy course - More detailed course. Recommended to go though all the videos and labs.
ACloudGuru course - Course is good for overview, itself is not sufficient to pass the exam. Certainly recommended to go through Ryan's 'Exam Tips' for each section, before a day or two of the exam.
White Papers - Storage, Architecting best practices are must.
FAQs and Documentation - Core services such as EC2 (including cost models), EBS (PIOPS,RAID Configuration), AutoScaling, ELB, Route53, CloudFormation, S3, CloudFront, Kinesis. I got some questions on OpsWorks, ElasticBeansTalk as well.
I got a question on Docker layer with OpsWorks too.
Practice Exam was very tough. I also took WhizLabs practice exams for $25 or so. well worth, it gives you a lot of good questions to practice, which is really helpful.