sorry if obvious: if you're going to compare with Jira, then my first question is "but does it scale?"
Everybody hates Jira, but it scales to 100,000+ issues across dozens of teams. Even tiny teams (heh, any team that's live and/or has a PM) quickly generate 1000s of issues and JQL is *godlike* in sifting through this stuff. Engineers tell me about Trello and I say, "great place to start" knowing they'll come to the dark side soon enough.
thoughts?