The user interface, which makes it easy to use even if you are not familiar with workflows.
It could be useful to add some more templates in order to help new users to get used to its functionalities faster. I would like to see also an option to choose between different type of workflow engines (for example we needed something very specific so we had to build our own). For now, this solution has allowed us to have all our processes centralized at once without having to rely only on email threads as well as using several custom fields that other systems did not support.