The following article concerns yet another CM tool (ansible), but I think the author does an excellent job of explaining the benefits of transitioning away from shell scripts.
http://devopsu.com/blog/ansible-vs-shell-scripts/
quote 1:
What really surprised me was the response from some of these more famous devs. They basically said, “This is really cool, but I probably won’t read it since my manual-install/shell-script workflow is fine for now.”
I was a little shocked, but once I thought about it for a few minutes, I realized that their choice was perfectly sane and rational given what they knew about CM tools.
quote 2:
For them, using a CM tool meant weeks of effort learning complex concepts, struggling with a complex installation process, and maintaining that complex system over time. They were somewhat aware of the benefits, but the costs of using a CM tool just seemed too high to make it worth the effort.
The benefits over shell scripts are summarized at the end and I think they apply to all CM tools, puppet, chef, salt, ansible…
- Which method is most likely to end up in source control?
- Which method can be run multiple times safely with confidence?
- Which method can easily be run against multiple servers?
- Which method actually verifies (tests) your server for correctness?
- Which method can target certain servers easily (web, db, etc)?
- Which method supports easily templating your configuration files?
- Which method will grow to easily support your whole stack?
Hope this helps.