I was about to post your previous post rogerdv, located here it's the 3rd one viewtopic.php?f=7&t=62&start=80
Their website dates back news to 2004, last major version was v0.4 in 2007 here http://unigine.com/news/?page=8
Also have a development log here http://unigine.com/devlog/
Oil Rush doesn't really count as an example of the engines ease of use and versatility, as it was made by the owners of the engine, who naturally have supreme mastery over the engine.
The engines been around for 8 years, but only 80+ licenses? (most of them for simulations no doubt) Compare that to Unity's 800 000 licenses. The engine also isn't that expensive, there must be a reason why hardly anyone uses it for games development.
It does have open source roots.
But doesn't support any A.i middleware.
It does support speedtree
Supports a form of destructible environment. http://www.youtube.com/watch?v=wvNRSOju5JM
Has a visual scripting system in alpha stage, said not to be ready for production use, too bad.
Full linux support will save time.
Since the graphics capability of unigine will go mostly unused, it's not worth the development speed hit compared to more established engines like unity and gamebryo. But if Inxile is planning to spend practically no money on technology, (likely) unigine appears to compare favorably against it's open source and cheap competition, like ogre3D, C4, and Torque. Also considering they're being given the engine for free, maybe they'll probably get preferential support treatment.