On July 10th we dropped from 1 to 2 on our two biggest keywords for our site that had held #1 for 7+ years. Ouch.
My gut says this update elevated bigger brands (bigger companies). What is interesting is that the #1 holder is not a direct competitor, but does offer a smaller competing service using the same keywords. Think of Amazon having a "store" selling Widgets. So even though our site is only about Widgets, their "subsite" now outranks us.