Great article. We've just moved a large portion of our async jobs over from Resque to Que because of the huge benefits you get from transactional enqueuing and processing. Performance seems good so far, and if it really becomes an issue, running two queuing systems side by side (one transactional, one high-throughput) seems viable.

We're super cautious about long-running transactions anyway, as they cause a load of other issues (e.g. http://www.databasesoup.com/2013/11/alter-table-and-downtime... - full blog post coming soon!)