Personally, if it is the night flight I'd go EVA and enjoy that great service and sleep combined with the earlier arrival into Beijing. When traveling in F I want a decently significant amount of time to be awake and receive the service level & enjoy the amenities while also some solid sleep.

Now if the miles don't mean much to you (eg, they won't put you close to being able to go on another premium cabin trip) or you'd really like to experience a first class trip go for it and don't look back.