Prefect and Apache Airflow defines logic in a pure Python code, while StackStorm uses a YAML-structured Workflow called Orquesta [1] supporting different logic patterns (parallel, merge, concurrency, join, retries, pause, ask, nested subworkflows, etc) [2] with Jinja and YAQL [3] support. YAQL is especially interesting one where Jinja is not enough.
There's also a bi-directional ChatOps framework you can tie with the workflows to make the experience more interactive.
So you can listen on events (could be a chat command) from 3rd party services, do some rule filtering & matching (all in YAML), and trigger workflows with the logic that runs actions in other tool(s) and service(s).
StackStorm has Exchange [4], - a collection of 100+ plugin integrations with different tools and services contributed and supported by community to make that building blocks juggling easier.
[1] https://docs.stackstorm.com/orquesta/index.html
[2] https://github.com/StackStorm/st2/tree/master/contrib/exampl...