I'm skeptical of your 10x less code claim. You can definitely get into broken state problems in CloudFormation - with no recourse but to blow it all away and start over. And despite being a native tool, CloudFormation support for new features and services in AWS is often spotty/missing.
That said, my experience has been that both CloudFormation and Terraform are irritating, just in different ways; they both are warty.
I do ultimately prefer Terraform - even in a single-cloud setup.
Some specific services (namely Data Pipeline) aren’t supported in Terraform. However, some parameters like Enhanced VPC routing in Redshift clusters is supported by Terraform but not CloudFormation.
The rule of thumb that you should generally stick to CloudFormation if you are full bore invested into AWS has some truth.
My issues with CloudFormation are lack of control over rollbacks, missing features for existing and mature services like the above, and forcing me to use custom resources to do anything that vaguely resembles coding that Terraform does just fine like IP address math functions.
That said, my experience has been that both CloudFormation and Terraform are irritating, just in different ways; they both are warty.
I do ultimately prefer Terraform - even in a single-cloud setup.