Analyses are never queued, they run less than a second after a git push.
The status of a commit or pull request is updated in just a few seconds!
Every analysis runs in a throwable and isolated environment.
The code is thrown away once the analysis has finished running.
Already running PHP CodeSniffer or PHP-CS-Fixer on your CI platform? PrettyCI can help you build software faster!
Running tools sequentially on the same job runner means slower developer feedback.
It also means that a failure in the first job will stop the whole build. Getting a green build becomes a multi-step hassle.
Parallelizing jobs is better: jobs finish earlier and both will run no matter what. However this is costly as it requires more runners. Coding style jobs taking runners from tests means jobs can pile up and queue.
Using PrettyCI for validating coding style means that more runners will be available for your tests (or that less runners will be needed at all). And since PrettyCI does not queue jobs at all, coding style status is usually available the moment a pull request is open.
PrettyCI guarantees the fastest feedback loop while keeping costs under control.
PrettyCI is no longer active, you can read more about it here.