We are converting AWS Lambdas from Java due to excessive cold start times. Usage: These lambdas handle XML and JSON payloads, they use s3, API Gateway, RDS, DynamoDB, and external API's. Most of our developers are only experienced in java. These three languages (Go, Node.js, and Python) were discussed, but no consensus has been reached yet.
I've worked with all three of these languages and also with Java developers converting to these languages and far and away Go is the easier one to convert to. With the improved cold-start times and the ease of conversion for a Java developer, it is a no-brainer for me.
The hardest part of the conversion though is going to be the lack of traditional Classes so you have to be mindful of that, but Go Structs and interfaces tend to make up for what is lost there.
Full Disclosure: I'm a 95% Go convert (from Python) at this point in time.
Although I am primarily a Javascript developer myself, I used Go to build AWS lambda in a similar scenario to yours. AWS libraries felt better integrated on the Go side, I believe due to the language itself (e.g. how JSON objects are handled in go). Besides that performance of Go is much superior. But on the cons side; community is far smaller around Go, compared to Javascript. That is easy notice if you look at repos of community-maintained libraries for Go. That can feel a bit unreliable.