To me, great software is beautiful software.
Obviously, the primary concern is that the software works properly, that it does what it is supposed to. But if that is all, the software will never be great.
Here are my conditions that great software must meet, from most important to least important. But they all matter!
- The user experience. Does the software let the user reach their goals quickly and efficiently? User satisfaction rather than ease of use. Great software is not necessarily simple, but it does get out of the way.