The ability for multiple users in different locations can work together from their desktops or mobile devices as well as sharing files with other parties via email is excellent! There are some minor issues that could be improved but they have been addressed since release date so no big deal there either.
It's great because it allows you to view your geological models anywhere without having physical copies at all times on site - even if we're away during field trips etc this helps us get our jobs done quickly when back home again rather than spending long periods waiting around trying to find something specific while out visiting clients/sites.