VSys Web is a manually synchronized (offline) system, which is only updated with the current information in your database when you explicitly run the synchronization process. As such it is limited: with VSys Web, changes made in your system are not reflected in VSys One immediately; hours and applications entered by volunteers don't show up in your system immediately; volunteers can't do live searches for jobs and part of your data is held by an outside organization (Bespoke Software) as part of the process. (VSys Web is available for self-hosting; if you're doing that, this limitation is not relevant).
VSys Live is entirely different. VSys Live runs directly from within your IT department (or in our datacenter if we're hosting VSys for you), and works directly with your live database. It also offers: