It definitively is neither pretty, discoverable nor intuitive, but in the hands of experienced power users (who have spent a lot of time learning the UI), it works really well. I have seen people (who have used the system probably for > 10 years) dig the most arcane information out in seconds, navigating through about ten different views without ever touching a mouse.

It's a UI from another era, but if you take the time to learn it properly, it can be very efficient.