Eurogamer got their hands on End of Nations at E3 last month and have a lot to say about it!
 

"Private instances are akin to a classical raid or dungeon. This is where you group with three or four others to run a more scripted, sculpted and challenging mission, and where the commander classes come into play. Any commander will have access to a wide range of other vehicle units and tactical options; it's more a specialisation than a strait-jacketing restriction."

“But in the grand scale of the World Map and the free-form, large-scale multiplayer of its social instances, it's possible to catch a glimpse of something very rare indeed: a completely new way to play RTS games.”

They talk more about their impressions of map sizes, the variety of combat theatres, graphics and overall feel, and more. Read the rest of the article over at Eurogamer!