Sure, the dialogue doesn't always make sense to the plot, but that's because the plot is so slight that the characters have time to talk. A lot of the dialogue is in non sequitar form, and for some reason a lot of people just can't get over that fact, mainly because they need their stories spoonfed to them. There are a lot of hilarious bits. For instance, Paul Newman's character has an anger problem, but he doesn't really want to hurt anybody and he always feels guilty for everything he does. At one point, as he's losing an argument with Strother Martin over some money he just walks over to a TV set and drops it out of a hotel window. He's not doing it to scare anybody, he's just frustrated. I bet more people feel like Newman's character than most of the ones you have ever seen in film. At another point, he kicks over a tiny trash can in a park, again frustrated in an argument over money. But, as he tries to walk away he gets an exasperated look on his face and walks back and puts the trashcan back in place. He simply felt too guilty. Now, maybe I just have a more finely tuned sense of humor than most people, but that cracked me up. I have felt, and done, that many, many times.
If Jim Jarmusch had made a Lee Marvin film, it might be a lot like this one. Jarmusch has built a career on just such storytelling. His filmmaking style might be more "continental," but that's mainly because he's a copycat and worships foreign filmmakers and is a bit of a snob. In fact, if some Frenchman had made this film and Alain Delon had Paul Newman's role and everyone was speaking French this might be lauded as a classic. Instead, it gets the short end of the stick from a lot of slow witted, unimaginative dopes. The dialogue is pretty funny, too. One of the best lines is quoted in a different review, so go read it there. I always liked the bit with the rock. But I won't spoil it here with my inaccurate memory.
So, if you can put up with the washed out cinematography, the only part I don't like, and enjoy a slow paced, subtle comedy with great actors who happen to have a talent for it, then you can't go wrong here.