Pest extend from phpunit, simpler to write, brought some modern feature, but not modern enough.

Good:

1. Extend from php-unit, compatible, easier to cope with exist php-unit project.
2. php-unit exist tools still works, such as Mockery
3. Easier to use, easier to write

Bad:

1. not modern enough, do not support python unit test framework, parameter inject(do not confuse with table driven unit tests inject through function arguments)

On the other side, php-stan is a bit old, boring, but has very strong extensibility.