Despite the fact that Edson's play won the Pulitzer Prize, some of the reviews of Wit were not completely favorable. There is a wide range of opinions of the play, with many critical reviewers claiming that the awkwardness of a first-time playwright shows through. Overall, however, most critics applaud the work.

Wit won not only the Pulitzer Prize but also the Drama Desk Award, the Lucille Lortel Award, the New York Drama Critics Circle Award, and the Outer Critics Circle Award. In addition, Kathleen Chalfant, who played the main character in the off-Broadway production as well as in a London production, also won several awards for her performance, including the coveted Obie. Other aspects of the play in performance, such as its direction by Derek Anson Jones (a former high school friend of Edson), its production, and its lighting, also won prizes.

The play was first produced in 1995 at the South Coast Repertory Company in Costa Mesa, California, where it ran for seven weeks to rave reviews. But it took two more years for the play to find its way to New York audiences, where it won nearly every drama award given for an off-Broadway play. The New York Times reviewer Peter Marks calls Wit a "brutally human and beautifully layered new play." Marks also claims that by the end of the play "you feel both enlightened and, in a strange way, enormously comforted."

A year later, after the play moved to another New York theater and took on a new cast, the New York Post's Donald Lyons refers to the play as being a "great (and hilarious) play." Lyons also notes that Edson uses a "tricky structure, full of metatheatrical interjections" (such as the main character turning to talk directly to the audience) but that Edson uses these ploys not for fun but rather to exemplify the "urgency of her [Vivian Bearing's] suffering." Another New York Post critic, Liz Smith, calls Wit an "incredibly witty and touching play."

However, Tom Sime of the Dallas Morning News (writing from New York) claims that Wit keeps the main character of Vivian Bearing "so busy addressing the audience directly that she can't flesh out her character by showing us her behavior." Sime also states that Edson's play only shows a "stereotypical view of the medical profession." Sime continues, "Ms. Edson writes a moving, tender ending—but then ruins it with a gratuitous and melodramatic additional scene, one last dig at those heartless M.D.'s. Given the great mysteries Ms. Edson has tried to explore, this closing stitch-up is crude and leaves Wit itself resembling a procedure gone awry."

Countering this opinion is John McCallum's review for The Australian. McCallum claims "the brilliance of Margaret Edson's script" is partly due to "the metatheatrical playfulness with which Vivian keeps commenting ironically on the show." And although Lloyd Rose of the Washington Post feels that the "gooey ending seems unworthy of Edson's heroine," he also claims, "Edson's frankness about the clinical awfulness of modern death is what makes Wit such a strong theater experience."

Aside from the reviews from the usual newspaper and magazine critics, there have also been comments about Edson's play from the medical profession. Some doctors have praised Edson's efforts to expose the callous treatment that many patients experience, especially in research (and/or teaching) hospitals. Other doctors agree with Abigail Zuger, who has stated that after seeing the play she felt very depressed.

Zuger writes in her essay "When the Patient, Not the Doctor, Becomes the Hero" that Edson's play shows the worst of the profession. To back up her statement, Zuger...