Some projects may benefit from using Omnibus; being able to produce deliverables which are just installed by the package manager. However, there is a significant learning curve and investment of time required for the debugging process in order to get your package building with Omnibus.
I finally said screw all that and I've resorted to shell scripts + packer building my images on amazon. Now my builds don't require a complicated omnibus builder host to be configured, or even ruby to be installed and god damnit, I don't have to worry about doing a bundle update to get the latest chef-sugar or omnibus gem to get it to work.
I'm tired of these complicated systems. Every new piece of tech in your stack should be considered carefully. I could barely explain Omnibus to my dev team, even though I knew exactly how it worked and how all the packages were built on every build.
Omnibus is a great project with a lot of contributors, but users beware - it comes at a price of time and complexity.