Just to include this in the discussion, here's some major features that have been added over the last year (but there's a huge amount of small ones too):

- End-to-End State Encryption - lets you encrypt your state-file end-to-end, either with a key management system like AWS KMS, or static keys.

- Early Evaluation - the ability to parameterize initialiation-time values, like module versions and sources, backend configuration parameters, etc. and keep them DRY.

- Provider Iteration - lets you use for_each with providers, e.g. create one provider per region, something that currently requires a bunch of copy-paste, or tools like Terragrunt

- -exclude flag - the opposite of the -target flag, letting you skip planning/applying certain resources.

Probably the best way to see a summary is to check out the release blog posts for 1.7[0], 1.8[1], and 1.9[2], as well as TFA itself. If you'd like to learn more, I recommend taking a look at the related docs, too.

[0]: https://opentofu.org/blog/opentofu-1-7-0/

[1]: https://opentofu.org/blog/opentofu-1-8-0/

[2]: https://opentofu.org/blog/opentofu-1-9-0/

Disclaimer: involved in opentofu