I agree! My experience with test generation tools was also lukewarm which is why we founded Checksum.

> How is the product different from the other test generation tools

We train our models based on real user sessions. So our tests are: 1. Completely auto-generated 2. Achieve high coverage of real user flows, including detecting edge cases 3. Automatically maintained and execute with our models so they are less flakey.

> How do you check if the are testing the intended behavior

Our models are trained on many real sessions so it learns how your website (and others) should behave. In that sense, it's similar to a manual QA tester which can detect bugs. To supplement for functionality that is not obvious by the UI, we are now looking at adding LLMs to parse code, but most of the functionality can be inferred from the UI