Terraform can get ugly for a large codebase. You have a lot of power with an actual programming language instead of YAML. But CDK is more complicated and the learning curve is higher.
My preference would be Terraform for small-mid sized infra and CDK for larger installations where code abstraction and reuse was more important.
But they both disappoint in their own ways. Orchestration is the great unsolved problem of the cloud.
To add to that; if you're dealing with multiple cloud providers it's a lot nicer to push a standard configuration, say networking, into a type system. Then you implement interfaces that accept that configuration and handle the provider specific bits.
That way the day-to-day tweaking of the config is the same, regardless of provider.
I'm probably never going to end up switching completely between providers, but I like having the ability to mix and match services if I do need to.
wat
The rationale is that CDK/CFN seems to work more reliably "at scale" for commonly used stacks due to low drama rollbacks etc. Roles that are primarily infra tend to not mind using aws focused tooling.
For devs, the documentation and usability of terraform is just better, plus the wide range of 3rd party integrations is handy. While it can be fiddly / not as scalable it's also a lot easier to adopt resources or refactor stuff which you tend to need more with "precious" long lived app resources.
CDK is great if you are only using AWS but Documentation sucks. I actually worked on CFN team and we interacted a lot with CDK Team.
It's actually written in TypeScript and then constructs are converted to other languages using Projen
Terraform is for when you are doing large projects in company, and want to have additional management features that CDK doesn't have.
On the flip side, for personal projects, you can get away with using boto3 library with the api it provides to create infrastructure, considering infrastructure probably won't change much, and its free. You pretty much just have to write a little wrapper to create the resource if it doesn't exist, then modify its attributes whether its just been created or if it already exists.
CDK, and pure cloudformation, and others are somewhere in between
