It's good as claimed...albeit still expensive...

" AeroVironment's findings appear to confirm Altairnano's claims that the battery should be good for tens of thousands of cycles equivalent to 500,000 miles of vehicle travel."

" The second big piece of news was Dan Elliott's announcement that an upgraded battery packis in the works that should give their SUT a range of between 200-250 miles."

http://www.evworld.com/article.cfm?storyid=1258