It is funny, every time I have used beanstalk over the years I have put it in thinking I'll replace it later. I never have. Multiple startups I have left years ago are still running it, untouched years later. No one mentions it probably because it didn't do anything but run. I wish the same could be said for RabbitMQ.
>>mianos+(OP)
I've used RabbitMQ on several projects over the last decade or more, and have never once known it to fail.
It can be tricky to configure it you want clustering, or have fancy requirements (e.g. client certificate authentication), but once running, it's solid.