I wrote this list last time this question came around, and I hope it will be of some use to you.

Mark Atwood Lawrence's The Vietnam War: A Concise International History is a great work to refresh your knowledge about the overall war. It covers many different perspectives of the war into one concise narrative which is very useful for beginners and experts alike, if only for reference. It's far balanced and more scholarly than other alternatives out there (Whether it be Karnow or Halberstam).

Christian G. Appy's Working-Class War: American Combat Soldiers and Vietnam. A great introduction to the overall experience of the American combat soldier in South Vietnam, this is a scholarly approach to the topic with much to reveal about the experiences of the men who were sent to South Vietnam. An alternative to this book who would like a less scholarly approach would be James Ebert's A Life in a Year: The American Infantryman in Vietnam.

Robert K. Brigham's ARVN: life and death in the South Vietnamese Army and Andrew Wiest's Vietnam's Forgotten Army: Heroism and Betrayal in the ARVN are both indispensable in revealing the complexities and realities behind the often maligned image of the South Vietnamese Army during the Vietnam War. Using both macro and micro historical approaches to the topic, Brigham and Wiest deepens the understanding of the war beyond simple stereotypes.

Hanoi's War: An International History of the War for Peace in Vietnam by Lien-Hang T. Nguyen belongs to a new era of scholarship focusing on putting the Vietnam War into global history and the involvement of other nations beyond the United States, North Vietnam, the Soviet Union, and South Vietnam. Nguyen's book is all about contextualizing the decisions, events, and negotiations that occurred throughout the war in an international context.

Edward Miller's Misalliance: Ngo Dinh Diem, the United States, and the Fate of South Vietnam is an important book that asks difficult questions about Ngo Dinh Diem and manages to give a more nuanced and fair image of Diem as a politician and the South Vietnamese context surrounding those early years of the war up until his death.

Triumph Revisited: Historians Battle for the Vietnam War by Andrew Wiest and Michael Doidge (ed.) This is a fantastic book about the current state of Vietnam War scholarship and the historiography surrounding the war. What are the current debates? Where is the field going? Why is the orthodox vs. revisionist debate such a pressing matter in the United States, or is it? For those who desire to study the Vietnam War at an academic level, this is a great place to start.

China and the Vietnam Wars, 1950-1975 by Qiang Zhai. It's never wise to ignore other actors in the larger drama of the Vietnam War. China plays a very important role in modern Vietnamese history and this book tells you exactly why. From the Indochina War to the Sino-Vietnamese War of 1979, China's view of Vietnam was constantly changing. From helping Vietnam to waging war against it, understanding China's place in the conflict is vital.

Making Sense of the Vietnam Wars: Local, National, and Transnational Perspectives by Marilyn B. Young and Mark Philip Bradley (ed.). This is a collection of essays surrounding different aspects of the Vietnam War out of new approaches and historiographical debates. It's a good book to read to gain some new perspectives and follows in the same tradition of Triumph Revisited although not as focused on the historiography as much.

... And then there's always my own scholarly research, Phan Chot’s Choice: Agency and Motivation among the Kit Carson Scouts during the Vietnam War, 1966–1973, which I can send a link for you to read.

BTW I've heard the Ken Burns documentary on Vietnam was flawed/based on dated scholarship. Could someone explain this to me?

I've written about this here.