NATS and NSQ are better than SQS if you can deploy them yourself. ZeroMQ is a great option as well, but it probably will require some major brain changes, since it doesn't fit most people's mental model of what a queuing server looks like.
We do have a hosted version of NATS called NGS that is multi-cloud, multi-geo and is really easy to set up https://synadia.com/ngs
And, you probably know a little bit about NATS, too, since, you know, you wrote it! :)