What I really like about The Things They Carried, in addition to O'Brien's writing style, is that it is such an introspective look at the Vietnam War. Most of what I have read have been firsthand accounts or excellent historical fiction that shows the detail of the fighting and what it was like for soldiers, but I feel O'Brien's work deals much more with the aftermath, and does so in a way that leaves some interpretation to the reader.
The Things They Carried is a great book for teaching both reading and writing in the English classroom. Tim O'Brien devotes some chapters to the events of the war and the aftermath of his and other's experiences there, and those chapters have the power to convey the experience, but the chapters that fall into the meta-fiction category are what I find most interesting. Chapters such as "How to Tell a War Story" and others challenge the reader to think about truth in writing and how authors can best convey the meaning of their writing. At one point he says, "a story truth is sometimes more true than a happening truth." He challenges the reader to question the truth of his war chapters and decided whether the true truth is more important than the truth they learn from reading the story he has created. I have my students use that concept as a touch stone for other literature we read during the year.
I feel that this collection of short stories is a very accurate description of war time - O'Brien manages to capture the characters of soldiers fighting in Vietnam incredibly well and very realistically. Of course, this is fiction, but at the same time, O'Brien's first-hand experience in Vietnam gives his work a real authority that should make us be very aware of the realities of war and in particular the sacrifices made by so many American soldiers in terrible conditions.
This question might be better suited as a discussion post. I'm not sure if you're asking someone's personal opinion of O'Brien's collection of stories or if you're asking a literary analysis question; so I'll answer it both ways.
Personally, I haven't read any other Vietnam War stories that I've appreciated more than O'Brien's. His first-hand experiences as a combat soldier during the war make his stories more poignant and credible. My favorite story from The Things They Carried is "In the Field" which features the band of men searching for Kiowa's body in the rice fields. Jimmy Cross's inner turmoil in this story is moving and realistic, as is Billy's guilt over a rookie move which led to Kiowa's death.
From a literary standpoint, The Things They Carried offers an interesting challenge to critics. It is clear that O'Brien blurs the line between fact and fiction, and his tone throughout the stories offers more truth than literary effect. Similarly, the continuing characters from story to story make the collection read more like a novel with chapters than like separate short stories, and I believe that this causes readers to get more involved in the characters and their fates.
My dad is a Vietnam Vet, and I once asked him if he had heard of Tim O'Brien. He had not; so I gave him a copy of The Things They Carried. He read the title story, but couldn't get through any more. He said that they were too realistic--in an ironic sense, that is an accomplishment and also an illustration of the integrity of O'Brien's portrayal of a soldier's life during that turbulent time.
I am not sure if you're referring to the short story "The Things They Carried" or the collection of O'Brien's short stories that shares the same title, so I will respond to your question as if you're asking about the story. I hope this is what you're looking for!
I believe that Tim O'Brien's use of his character's belongings to reveal who they truly are as human beings is exceptionally good. One can tell a great deal about each character simply by learning about the material possessions each holds dear. This concept is certainly reflective of real life; people tend to cling to those things that they feel form some kind of connection to the people, places, or things that matter most to them. Those "things" not only serve as indicators of who the characters are, but also comfort those who own them and give them hope of returning to the things they represent.