Redis-Queue (RQ) Task Queues in Production
Celery works in production, as far as I know, for Python/Django, the most mature implementation of synchronous task queue/job queue based on distributed message passing, with Redis as a broker works just fine.
What you would need in production is not only send a simple message but a high-level API for:

Scale, auto-scale.
Real-time monitor.
Task schedulers.
Prioritization.
Multi broker support.
Workflow based tasks.

For which Celery is ready.
I recently started having a need for a task queue in my Django program, and I'm worried about how robust it will be in the future or what will need to be overcome for a production deployment. 
I'm using the Redis-Queue or RQ library for Python, which markets itself as easier to learn and use than something like Celery (which I haven't quite learned). Does anyone have any input on this? Do you think RQ coupled with Redis would be OK in production, or would you use something else? What do large-scale apps use for task queueing?