Reviewing with River

Do you look at the plot, the characters, and the way that the author puts words together?

Absolutely, as these elements are all important and form a major component of the author's style and voice. Word choices are so important in shaping a story, a character, and a theme.

Do you like stories that have a lot of action or a lot of character development?
I like both, but character development makes a story full of action that much deeper so I would put slightly more emphasis on that.

Do you like authors to use a lot of complicated words, or very simple words?
I don't really have a preference as long as the vocabulary is used correctly and adds to the story (i.e. isn't gratuitous)