I recently passed the certified developer exam with 88%. The Whizlabs practice papers were spot on and greatly help me to prepare the exam ahead with the confidence needed. The exam itself was a breeze and I finished with almost 45 min to spare. The Whizlabs practice papers goes quite deep into several topics like SNS, SQS, ElasticBean, DynamoDB in particular. I had very trick questions coming from SNS and SQS in particular. Overall great experience and would strongly recommend to anyone preparing for the AWS CDA exam . Good Luck folks.