Does anyone have any experience taking the overnight train from Beijing to Xi'An? or even experience with the two-berth sleepers?

There are two of us traveling together (a couple) and we are considering upgrading to this sort of travel by train.

Is it worth the extra cost? I've heard that you even get your own private bathroom? Part of me thinks it would be nice not to have to worry about listening to other snorers on the train journey.