We've been really happy with Clubhouse for project organization / task management / kanban board while developing FeaturePeek. The featureset is rich and the UI uncluttered. Clubhouse is different in that it makes some assumptions on how things should be (workflow state, the relationships between stories/epics/milestones, etc). having it be opinionated from the start helps you hit the ground running, while still being editable / extensible for tweaking things to your liking.
The pricing is spot-on too – a flat $10/month for teams of 10 or less. This really made it attractive to us to try out.
If you think Trello is too basic / lightweight but Jira is too full-featured / heavy, you should give Clubhouse a shot – I think you'll be pleasantly surprised.