Goamz suffers from the same problem that all the libraries that try to hide the actual API do... that they can't keep up. Even boto has this problem as keeping up with the latest version isn't always easy.
IMO the best of the AWS libs is github.com/bmizerany/aws4. It only wraps the auth, the API and results are up to you. This requires more work but means you never have to worry about the lib keeping up with the API. With something that moves as fast as AWS this is great.
1. Announce something in a blog post (sometimes get everyone really excited)
2. Add access to that feature/setting in the AWS Web UI
3. Add access to that in the official API
4. Add access to that in aws-cli
5. Add access to that in cloud formation stack creation
It seems sometimes weeks and months lag between steps (e.g. steps 2 to 3).
I'm not sure that's true of all the client libraries - I'm pretty sure that the Java library is used heavily internally within Amazon to leverage AWS services. Just look at the release history: https://github.com/aws/aws-sdk-java/releases
But you're right, maintaining even a blessed third-party library like boto is a massive undertaking: 437 contributors, 431 open issues, 192 open PRs. Competing against CloudFormation using anything other than the Java client library is crazy IMO.
But anyway, goamz is "Hashicorp's" AWS Go SDK in that Hashicorp forked it and refused to work with the larger community because it's "critical" to their business. This has, at least until super recently, stranded certain functionality into the different forks and severely fractured the AWS Go offerings. True story.
Ultimately, what the Go community probably needs most is Amazon to step up and support a Go SDK officially. The Java, Ruby, .Net, and even Python SDK's are very robust at this point. I can't speak to the others.
Good to hear about the .NET library. I hadn't heard the story about goamz, that's unfortunate. I do know that there are SDKs which Amazon _only_ make available in Java and Python, e.g. the Kinesis Client Library (http://docs.aws.amazon.com/kinesis/latest/dev/kinesis-record...).
IMO the best of the AWS libs is github.com/bmizerany/aws4. It only wraps the auth, the API and results are up to you. This requires more work but means you never have to worry about the lib keeping up with the API. With something that moves as fast as AWS this is great.