I end up going back to Trello. - Years ago I was using PivotalTracker. But Trello was way better. Every couple of months I try to see if there is anything better, that's when I check out Asana and go back to Trello.
The other problem with PT is that it promotes a bottom-up view of your project rather than a top-down view. You end up missing the forest for the trees. With Trello, I can create a list for a high-level goal like "Validate that users want the features we're building" and then list sub-tasks within that.