Hey there, I'd say the key difference between Matterhorn and Trello is that Matterhorn is more aimed at allowing a team to maintain multiple projects at once - for example overviewing the progress of all your projects at once and planning your project from a global planner rather than having to set due dates on individual tickets.
This sounds very good. I see a calendar icon but wonder what the calendar actually looks like. A limited trial may help potential users answer questions like that. Either way, impressive and will keep an eye on this.
