Queue depth status
Using Jamroom
Email is was not a big of a deal for me, but now that you mention it I think it became much more relevent.
My use case was more for encoding priority. I encode to multiple formats; however only one is needed before the file is available to the player. I wanted to make sure that one gets processed right away so the user is not waiting.
I didn't think email was an issue, because I wasn't using the conversion server to send emails. But now that you mention it, I didn't realize emails were getting held up by conversions. I thought the email would get picked up by the email server regardless of the conversion jobs in the queue. I hope that is the case and maybe you can confirm.
If that's still true, one approach to prioritization is to dedicate servers to certain types of queue jobs; so that they don't get held up by conversions. However, I'd still like to assign a priority to the conversions.