Trial was designed to deliver an awesome experience writing DLang tests. If you have a big collection of unit tests, now it is easy to maintain and debug them. When you need a feature, you don't need to wait for someone to add it. You can add it yourself.
Trial provides a clean interface that allows you to extend the runner with any feature you want.
If you already use the dub test command adopting trial should be easy.
You can execute tests writen in unittest blocks, using spec format and test classes.
Everyone cares how they get the test results. Trial provides console, xunit, html and 3rd party reporters.