Author here. Fair. I never used Terraform beyond playing with it briefly, so I can’t really comment on the differences. I tend to choose CFN mostly because I’m familiar with it.
I'm in charge of cloud infrastructure at my company, and I've found that sticking with CloudFormation on AWS is more powerful and versatile than TerraForm, since TF isn't always a perfect mapping, where CFN is, with the caveat that it's sometimes months behind what their API can do.
To that end, over the years, I've come across a couple of tools which help write CFN templates and manage rollout keeping cross-stack dependencies in mind. If anyone does a lot of CFN, I highly recommend Troposphere (python abstraction for cloudformation) [1] and Stacker (manager stack rollout via dependency DAG) [2]
Fwiw terraform also lags behind what the underlying apis can do -- but it's a community effort and you can contribute to add the functionality you need, whereas with CFN you can only ask your TAM (iff you have one!) to ask the internal team(s) (not sure if only CFN team or only the service team or both have to implement something) to prioritize your feature request.
