Kanbanize. I also looked at LeanKit Kanban before. It seems to be almost similar, maybe a bit better, but a bit more expensive for our team. Not sure what you mean with Github issues, I don't think Kanbanize has Github connection but there is an api so you should be able to build one if you need it.
I'm personally not a fan of rally - I've seen it in some larger environments and it really was a bit of a pig that felt like it was there to serve project managers and not the users. it tried to do too much and the UX was quite poor, buttons everywhere etc... A bit like jira.
Trello. Its flexible, powerful, and easy to integrate with other apps you use via Zapier and more (disclosure: I work on the Zapier team). I use that with OmniFocus' email drop to keep my todo list and due Trello cards synced, for instance.
