The ease at which we are able to connect with our customers through this platform is amazing! It's easy for us to get creative when designing solutions using their API; however not all problems can be solved by an online service like theirs (in fact most cannot).
We use it primarily as part of one project that involves collecting data from multiple sources into S3 buckets and then transferring those files back out via FTP or SFTP once they have been processed/changed within AWS services such as EC2 instances etc.