When it comes to Tom Clancy being a "good writer", a lot of people will answer this by simply taking a look at what he writes about. He seems to write a lot of about War and battle. So any fan of that could be attracted to his writing, and think of him as a good writer. I tend to look the quality of writing, and if everything goes together smoothly, as opposed to what he is writing about.
When writing modern day political and military novels, there is a clear and present danger associated with getting it wrong. Fortunately for Tom Clancy, he always gets the details correct. Whether his heroes are at war or at Patriot games, his compelling storytelling keeps me on the edge of my seat.