I think Terraform's multi-cloud support is a bit better than Cloudformation's. Jokes aside, I don't think the multi-cloud part is really the biggest selling point, the biggest selling points, for me, are:

- Much better than Cloudformation at telling you what it's going to change before you apply the changes and the ability to record those changes. (much better than those dreaded 'conditional' changes)

- The ability to import changes if you found some that were done outside of Terraform. It's not perfect, or easy, but mostly doable.

- The ability to look at the code, the state file and the plan to get a good representation of what's actually deployed.

Those three are more significant than it looks, but together it makes sure you:

- Don't get into a situation where automation is broken and you can only recover by rebuilding the stack.

- Don't get unexpected downtime because a change replaces a resource unexpectedly.

- Being able to track, record and manage changes in easy to read diffs and plans.