IMO, creating a nice set of modules/classes is almost always better than a monolithic script in terms of maintainability once your project gets beyond a couple hundred lines. A well-thought-out set of packages (and a nice set of tests!) will tend to be much easier to change/tune/update as time goes by, and you might even get some good re-use out of your code.

There typically is a very minor performance penalty for modularizing your code like this, but the maintainability payoff is generally more than worth it.