One of the areas where Trello really excels is representing agile workflows, as evidenced by the many organizations that use Trello for internal organization. That said, I think Trello's biggest strength is the huge amount of flexibility you get to develop and experiment with a system of organization that you're comfortable with.
You probably wouldn't guess this just from a glance at Trello's UI, which is surprisingly clean and uncluttered. At its core, it's just a bunch of cards on a board (and you can use it as such), but as this article mentions, you can pull in more powerful features like checklists and labels to represent almost any workflow you can think of. It's a surprisingly powerful, modular system.
I agree completely, I've tried many project management apps and the main problem I had with them was the lack of flexibility - each had their own idea how project management should look and you didn't have a lot to say. Trello on the other hand really allows you to adjust the workflow to team and project needs, the concept is both simple and powerful.
You probably wouldn't guess this just from a glance at Trello's UI, which is surprisingly clean and uncluttered. At its core, it's just a bunch of cards on a board (and you can use it as such), but as this article mentions, you can pull in more powerful features like checklists and labels to represent almost any workflow you can think of. It's a surprisingly powerful, modular system.