In my experience, this is the best, because it is very easy to organise your working process. I like the system of filters and boards it has. I have tried other stuff too, like Asana, Jira, even Monday. Those have their pros and cons too, but to me personally Youtrack is the preferred one, due to it's simplicity and inherent minimalism. I don't do rocket science, so maybe that's why I find it the most compelling.
Jira - The #1 software development tool used by agile teams. Jira Software is built for every member of your software team to plan, track, and release great software.
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.
OneLogin - On-demand SSO, directory integration, user provisioning and more
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.
AuthAnvil - AuthAnvil software is an integrated identity and access management tool designed to help IT managers service their networks, infrastructure network, and ensure that devices are safe and secure at all times. Read more about AuthAnvil.
Redmine - Flexible project management web application