I can't speak for others, but I can for Factor.io’s twist... (1) It is Open Source + Hosted + Pro. (2) The recipes ("workflows") can include multiple steps, sequential, and parallel activities; not just limited to if-this-then-that. (3) Workflows are defined programmatically using a Ruby-DSL. (4) You can create both actions and listeners (like events/monitors), though some of the others support this too. (5) It's been around for 2+ years, built with feedback from 100+ dev teams, and used by 1000s.