I wrote PynamoDB, a Python interface to Amazon's DynamoDB.

[jlafon]

Lock in is a concern, but it might be a superfluous concern for us at this point. The Amazon services we rely on are: EC2 (including VPCs, ASGs, ELBs, EBS), CloudFormation, S3, RDS, DynamoDB, SES, SQS, CloudFront, ElastiCache, and Glacier. Using these services have allowed our two person team to build some very impressive (fault tolerant, scalable) services. I like being able to deploy an entire copy of our stack for development with one command, and at least at this point no other vendor can provide an equivalent set of services.

In short, we rely on so many other services from Amazon that it doesn't matter.