There's not too much to say about the license, it clearly is neither Open Source nor Free Software as those two models give the end user rights. The Business Source License only gives some rights to some users.
If you run a business, especially in the technology space, using software that's licensed under the Business Source License is a serious business risk.
Vendors who provide competitive services built on our community products will no longer be able to incorporate future releases, bug fixes, or security patches contributed to our products.
Just to make it clear: if your business uses HashiCorp products, your entire business will forever depend on HashiCorps behavior. Whenever they choose to enter a new business field they can make it impossible for you to continue to do your business as they consider you a competitor from then on.
Edit 2023-08-25: Terraform was forked: https://opentf.org/announcement. I think that's a good thing as I had just started to work with it and had stopped due to the vague and unfriendly license change.
Edit 2023-09-05: The OpenTF repo is now open, releases will hopefully come out soon.