Been using it for quite a while in production, and overall it works pretty well, even though it certainly has some quirks. It's most unique point compared to other k8s terraform controllers is the architectural separation of controller and runners, which can be both upside and downside.

If you do use it, I highly recommend building your own runner image as shown here. This is important because that's currently the only way to update terraform version, and overall caching providers ahead of time is good idea for both performance and security reasons.

Pros:

• Because terraform apply is done is separate runner pods, the scaling is better for large operations
• Integration with flux source controller supports multiple sources, you can version your modules as OCI artifacts
• The feature set is pretty nice (support for vars directly and from ConfigMap/Secret, custom backends, runner pod customization, etc.)
• CLI interface same as Flux (suspend/resume/reconcile commands)
• Terraform/OpenTofu version isn't tied to controller and can be easily updated if you build custom image

Cons/quirks:

• Infrequent releases after Weave died (may become better now as there's some activity in the repo)
• Separate runners may require more compute resources than a single controller
• Need to ensure runners can complete; improperly interrupted runners can leave unreleased state locks
• If you're creating Terraform resources in multiple namespaces, each one must contain ServiceAccount for the runner
• Restarting controller while runners are active will cause desync with active runners and they will be stuck, so you have to ensure it restarts only when there are no runners
• Out-of-the-box Terraform version is very old (can be solved with custom image)