I used to use SQS but Postgres gives me everything I want. I can also do priority queueing and sorting.
I gave up on SQS when it couldn't be accessed from a VPC. AWS might have fixed that now.
All the other queueing mechanisms I investigated were dramatically more complex and heavyweight than Postgres SKIP LOCKED.
1. By combining services, 1 less service to manage in your stack (e.g. do your demo/local/qa envs all connect to Sqs?)
2. Postgres preserves your data if it goes down
3. You already have the tools on each machine and everybody knows the querying language to examine the stack
4. All your existing DB tools (e.g. backup solutions) automatically now cover your queue too, for free.
5. Performance is a non-issue for any company doing < 10m queue items a day.
If you are using the queue as a log of events (i.e. user actions), you get an atomic guarantee that the db data is updated and the event describing this update has been recorded.