I like that it is very customizable, has great reporting options for various metrics (such as time spent in queue), and allows users to create their own dashboards when needed.
The user interface could be much more intuitive at times; some tasks seem difficult or even impossible without extensive training. It's also somewhat expensive compared to other tools out there- especially if you're looking only for queuing/workflow products rather than an entire suite including scheduling apps etc.. For our organization this was helpful because we were able to set up queues easily and manage them from one central location using just SQL Server Management Studio instead of having several spreadsheets around.