It rarely happens, but when an author remembers that the game rules are only an abstraction, and not a verbatim description of the universe, then I like the story more. Some of the battles read like a game synopsis, which really ruins it for me.
I tend to prefer stories based around small units, especially if they also give face time to the techs and paper pushers.
If the hero and/or the unit they belong to are only of average quality, instead of the heroes that can do no wrong, I'll enjoy it more.
Putting in detail on the culture, history, and ecology of the planet they are on, rather than just noting it as the site of the battle, makes it better.
If it has anything to do with the Clans, then it isn't as great.