Kaufman and Hart's stage-play was a gem, hilarious and tightly constructed. Adapting it to film, however, drained much of the life out of it.
First of all, the film version comes across and formless and rambling. It's never clear what the central story is: is it the obnoxious houseguest vs. the owners of the house, or is it his secretary's love-affair, or is it something else? On stage, the division of the play into separate acts imposed a sense of order onto all of this, but in the movie its just stitched together. What's more, the movie adds brief scenes - Whiteside arriving in the town, the secretary skating with her boyfriend - that distract from the plot without adding anything.
Almost every good scene is defeated by incompetent choice of camera shots. Close-ups are brought in at inappropriate moments. The rhythm of the film is constantly in flux.
Monty Wooley does not, in my opinion, play the leading role very consistently. Some of the supporting performances are dreadful: the nurse, the young writer/newspaperman (one of the worst actors I've ever seen). Bette Davis is not bad, but her chemistry with Wooley is erratic; sometimes she laughs gently at him, other times she takes a hard-bitten cynical approach to his behavior. The problem is less with her than with the direction. Ann Sheridan and Billy Burke give the only really satisfying performances.
Bette Davis herself complained: "I felt the film was not directed in a very imaginative way. For me it was not a happy film to make--that it was a success, of course, did make me happy."