The ease of use, how quickly you can get up to speed with it's capabilities is great! It was not easy at first but once I got used to all its features we were able to solve our needs very well.
There are so many different ways that this software works in conjunction with other applications such as Microsoft Excel which allows us to do some pretty cool things like calculate ROI or determine if certain parts will be profitable or no longer viable over time. We have been using DnMx since about two years now where most companies would take weeks just learning what they could accomplish within their organization.