Office2013 is definitely a step forward compared with previous versions. Although the individual applications have some (limited) new features, he strongest improvements are to be found in the field of connectivity. A much better cloud (SkyDrive) integration, and a better integration in the field of social networking (Skype etc.).
This immediately brings me to another question. What is the added value of Office2013 compared with Office365?
If your business chooses for a full cloud solution, Office365 might be a better choice.
If cloud is not an option, I doubt if an upgrade to Office2013 is worth while.