I love that it is so simple for our team of 12 people to use! It's very intuitive with no learning curve at all - we have been using this software since day 1, when they first released their product (we are still in beta), but now even more features were added which makes us really happy as well.
The interface looks great too! What could be better? Nothing comes into my mind right away. We can do almost everything from one screen including assigning tickets/tasks etc., managing tasks lists or project plans etc., creating new users, adding contacts & sending emails out-of-the box without having to install anything else like other ticketing softwares require.