I should prolly mention that I was lucky enough to work with one of the Concourse authors, and also think it is awesome. Every other CI server I've used has induced rage!
I don't think it's hit version 1.0 yet, which would explain its rough edges. I find it interesting that it shares a lot of philosophies with Bosh.
That's meant more of a musing than a passive-aggressive complaint BTW. As someone that's scaled the "Bosh learning cliff" I'd like to see it used more widely.
Almost every team in Cloud Foundry has switched to using it and some projects out of Pivotal Labs are tinkering with it too.
I think that once the resources ecosystem grows and it becomes more approachable for beginners, Concourse has massive potential.