Travel by train or flight?

Hi Doris from Australia or anyone who can help me with my questions. I am debating wether I should travel by train from either Beijing or Shanghai to Guilin or fly. Mainly how is the scenery, safety, and comfort of the Chinese train services along those routes? I need to buy my round trip Airline ticket soon and am still lingering and unable to decide? I am flying into Beijing at the end of March 2015. If I fly my route will be from Seattle to Beijing-Shanghai-Guilin. Your advice will be appreciated. Thanks.