Even McAfee used to tell people to say "Mic-Af-ee". I had previously called them myself to find out for sure and that is what they told me; that was about five years ago.
The local cable provider here, Comcast, used to say "Mic-Af-ee" in their commercials and over the phone. Within the last year or so, it seemed to be just overnite, they started saying "Mac...". Very confusing. A friend of mine works for Cox communications in Las Vegas. He also stated that they used to say "Mic" but suddenly people there, including his employer, have changed their pronunciation of the word to "Mac".