There's a recent trip report of this journey on here - http://www.flyertalk.com/forum/trip-...n-beijing.html

I did Beijing -Xian a couple of weeks ago on a G train and opted for first, because, well - it's first
Depending on how many is in your party there was a separate 'cabin' in first with two rows of 3 seats facing each other with a table in the middle and more 'window space'. This cabin was enclosed up to about neck height.