I think it depends on how you would sell yourself in the essay. I also feel that those admission officer value both of your company brand in general and your personal experiences. I mean if you work for Microsoft, you might be a little bit more difficult to differentiate yourself from other candidates, but if you work for Amazon China (which is relatively new with more opportunities for personal growth), you might seem more unique to the bschools. I have heard a story from HBS that one ex-McKinsey analyst joined Amazon US just because he wanted to differentiate himself from other candidates to get into HBS.
However, after all of these considerations, your passion should always come first.