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.
It is a very, very slippery slope and it's seductive to put everything into Postgres at low scale but I've seen more places sunk by technical debt (because they can't move fast enough to catch up to parity with market demands, can't scale operationally with the budget, or address competitors' features) than ones that don't get enough traction where technical debt becomes a problem. But perhaps my experience is perversely biased and I'm just driven to over-engineer stuff because I've been routinely handed the reins of quite literally business non-viable software systems that were over-sold repeatedly while Silicon Valley sounds like it has the inverse problem of over-engineering for non-viable businesses.