I tried it end of August, and I must admit the whole concept sounded cool, but the interface was not intuitive. They seemed to have worked a lot on this and included powerful integrations.
I have started using it with my clients in my software development agency, which has made my life a million times easier.
The Trello integration is seamless, and I can give my clients complete visibility.
I just took a couple of hours upfront to set up the perfect requests landing page for my clients and told them to use this as a "common interface to deal with my To-do-list" so that they don't get involved in my Trello board.
Keep up the good work Isla folks