The usability. Very easy to use out of the box and works flawlessly for both users and admins. Very robust and open-minded with many options for many tasks all built in the software out the door.
GUI too pretty (is that possible?) Me and my team feel the GUI looks great, but a bit too great in the idea that it can get a bit cumbersome with all the options and modern look. Needs to be as simple as a ATM interface. Obviously we would need to have all the functions, but perhaps broken down more within other modules or windows.
Making this work in house only over your LAN or extended LAN (site to site) is quite easy to setup and get rolling. If you want the full cloud based setup to be fully functional. There is a bit more expertise needed. But it's still very capable to setup and get rolling fast.
We have a 2nd site in Auckland, New Zealand which is 18 hour time difference from our main site. This has allowed us to troubleshoot, update and other functions that have given headaches in the past