I have read about a half dozen of Miers' pieces so far--nothing particularly good or bad about any of them. They are pretty standard practitioner fare, apparently fully competent, but seemingly no better or worse than a thousand lawyers at good firms in Chicago would do. There is none of the flair that showed in many of Roberts' memos in the Reagan Administration. I've read nothing intellectually substantial by Miers so far, but then I've just started working through the list. If she has any sharp analytical skills, they are not apparent in the pieces I've read. Given Miers' genuine success in practice, I suspect that she is a better advisor and negotiator than writer.
One thing stands out: most of Miers' published writing that I've read is stimulated by her close ties to the ABA.