Was he an effective Secretary of Defense? Was he an honest politician? What sort of criticism did he receive during and after his time in office?
We had a discussion about Robert McNamara about six months ago.
http://www.reddit.com/r/AskHistorians/comments/1k5quy/is_robert_mcnamara_rightfully_hated/
Effective? Depends on your definition really. He usurped power from the Joint Chiefs, centralizing and at times micromanaging warmaking under the SecDef. Of course the war in question was undoubtly a fiasco, so that's probably not a good thing.
Honest? Hell no. If you're a masochist and follow his many attempts to rewrite history in the last 20 years, he keeps changing his story. Supposedly Jackie O convinced him early on that the war in Vietnam was fundamentally wrong, but he went through with it anyways. Which is frankly a really wierd defense, even on the off chance it's true. He's made various spurious anecdotes about Camelot that have been proven to be factually untrue, including that he picked JFK's grave site.
Criticism? I'm assuming you saw Fog of War? It included a contemporaneous clip when he first became SecDef. He was the poster child for JFK's whiz kids at the time. Supposedly a hard core technocrat, "with a mind like an IBM calculator." He was supposed to bring his business analytic skills to government, streamlining it all. To their credit, the JFK Administration didn't escalate the Cuban Missile Crisis and "won" the standoff (of course McNamara claims credit for this.) But Vietnam became known as "McNamara's War." He escalated the war repeatedly, and then when Tet happened, threw his hands up and walked away. In his various memoirs, he's since revealed how intellectually shallow he really is, stating that it wasn't until the 1990's that he realized the Vietnam War really started at the end of Japanese Occupation. Yet all the time, he has this blistering confidence in his beliefs.
Donald L. Hafner at BC summarized it the best.
"In Retrospect also seems to disappoint as a memoir ... seeming to confirm those characteristics alleged by McNamara's worst critics: that he is analytically shallow, emotionally remote, and unreflectively confident in the truth he happens to hold at any given moment."