Kanban is a few decades old, is time tested for project management and the best SDLC tool next to Jira. Compared to Jira it is lighter, has the same features, but supports better work collaboration. Most importantly it is freeware and is widely used, so knowledge of Kanban is a definite plus on you resume. It is also great for SaaS, IaaS and other cloud based work flows. It has good change management support.

I like the user interface of KanbanFlow. Different type of task and user is in different color so you can look in a look. Any user can use it in few minutes due to easy interface. Time estimation is also a good feature to be safe from project delay.

Its very lightweight, so it works very fast compare to other interfaces with a lot of graphics, for example as Trello has. In some instances, I prefer speed in exchange for some design features.