I love the library of steps which really allows to automate a lot, the usual setup for the projects I've worked on is:
1. Kick off the build for every PR
2. Run the Android Lint, make sure it does not detect any issues.
3. Run Detekt, make sure Kotlin code is in good shape.
4. Run unit tests (you write them, don't you?)
5. Change the version code automatically.
6. Build the app
7. Run integration tests
If we're talking about release candidate builds, we can run all previous steps, plus
1. If everything is fine, create the Github release
2. Then push the build to Google Play Beta/Fabric Beta
3. And finally notify the QA team
Huge time saver.
Plus, the support is always here to help you - to this date I never saw a question on Bitrise forums which was left unanswered by Bitrise team for more than 24 hours (the average time to answer, I think, is much shorter) - you can always be sure that if you have a question, it will be answered.
Sometimes (really rarely) the build might fail for no apparent reason, e.g. I had a situation when the build failed with the error which was introduced in another branch not merged into the PR which was being built. Maybe Bitrise misused the cache left from the previous build or something like that. In any case, the situation was fixed by rebuild and I never saw similar issues afterwards.
I would also love to have the ability to tweak the scheduled builds settings a bit more (e.g. I don't want to run my build every week, there is a specific set of builds which has to be run once in two weeks only). Scheduled builds do not allow me to do as of now.
It simply allowed us to easily automate A LOT of the tasks which previously were either done by hand or not done at all. Now it allows me as a developer to concentrate on coding/refactoring/automated testing and Bitrise will make sure everything that has to be done will be done in time and according to our processes.