CFengine, at least version 3, was probably the furthest away from string manipulation (and I was given the impression that text file content manipulation was considered a bad idea with it). What killed it was promise theory, which is actually a great theory and works quite well but made writing the bundles painfully hard and also hard to maintain. Also during the early days of v3 it was probably lacking a ton of essential functions so even if you were trying to do things the right way you would bump into feature limitations. I think this put a lot of people off adopting it widely and why Chef and Puppet did so well.
Puppet and Chef is actually quite good and I still prefer it to Ansible for a number of reasons. I've certainly run it fine in environments of many thousands of servers, though I can understand that it can implode for some people at scale if they design their deployments in a certain way or structure their manifests/cookbooks a certain way. That said I've certainly seen Ansible fold on much smaller infrastructure, but that is also down to a number of factors that can be avoided or mitigated. Idempotency with Puppet is really strong which is something you want if not every single system in your environment is ephemeral, with Chef it's almost as good with that but not always with the first run, with Ansible you have to specifically consider and aim for it when writing code for it in your playbooks.
The fact that you get used to having Chef or Puppet run e.g. every half an hour is a good thing, where Ansible runs are more ad-hoc. This leads me to another thing that bothers me and that is where people think it's a situation of having to use e.g. Puppet or Ansible as if they're conflicting choices for the same tasks. They have a lot of things in common, but Puppet is more for managing and ensuring changes in an idempotent, non-conflicting way while Ansible is more for doing something a bit like that but more for ad-hoc or orchestration tasks. I think it's good to use both but also be sure what you use it for, since one can do a bit of what the other thing is good at but doesn't do it so well.
For example, I would consider using Ansible to do deployments and releases, rotate SSH keys, execute failovers, or even to install the Puppet agent for the first time. I would use Puppet to deploy and update monitoring agents and configuration, user access, ensure directory permissions, configure system things like rsyslog, logrotate, Postfix, ntp, etc.