Review of Trello
Pros: Really clean UI, Kanban goodness
Cons: No overview/progress, can be hard to give enough structure
Buy? Yes, I recommend it.
I've tried a lot of project management tools out there over the past 10 years. Everything from simple issue trackers (Trac and Github Issues) to full on project management like Pivotal Tracker and Asana. Trello wins hands-down on the nice-to-use, beautiful interface, works in most-situations department.
I paid $9.99 per user/monthtrello.com
What do you think about Trello?