Datacenter Replication (DR) and GUI-based Visor management are part of enterprise edition.
However, GridGain Command Line Visor management (http://atlassian.gridgain.com/wiki/display/GG60/Command+Line+Interface) is part of open source edition.
Additionally, some of the other cool features provided as open source include different language connectivity (like C++, C#, HTTP), and off-heap storage.