Ask HN: Anyone using AWS Lambda or Azure functions successfully in production?

Anyone using AWS Lambda or similar serverless offering in production? Asking because we are about to launch a PaaS offering and wondering if users are more keen on a Heroku like offering or the on-demand code execution service like AWS Lambda and Azure functions. I personally feel current serverless offerings are not very suitable for large or complex development use cases. Perhaps it's good as a glue layer where you have to perform some event based actions, but not as your main backend? Any experiences and thoughts from your side?