What are some alternatives?
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Airflow - Airflow is a platform to programmaticaly author, schedule and monitor data pipelines.
Asana - Asana project management is an effort to re-imagine how we work together, through modern productivity software. Fast and versatile, Asana helps individuals and groups get more done.
Pipefy - The new development platform built for agile teams.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Pushwoosh - Push Notifications Service | Your Apps Can Talk!