Rat Race is not a cinematic masterpiece. It doesn’t have any depth of characterization, it has scene after unlikely scene of ridiculous goings-on, it has a cheap, melodramatic happy ending, and it will never be up for an Oscar.
That said, I laughed myself silly watching it. If you’re looking for some escapist comedy-for-comedy’s sake, this is a fine choice. Lots of favorite actors doing the kind of hamming they do best, a funny script, and little sense of taking itself seriously contribute to an enjoyable two hours.