The file submission referenced in this post is no longer available on File Exchange.
Anybody who has worked with MATLAB's polar plot is aware of its limitations (can't change properties, doesn't play nice with hold). Duane Hanselman (of "Mastering MATLAB" fame) took matters into his own hands. Duane's MMPOLAR adds these features and more. I was probably most impressed by its ability to work well with hold. He did a great job of resetting axes limits appropriately after you add lines to a plot. Duane also added a nice list of easily customizable properties.
Another nice thing about Duane's submission is that he conforms to MATLAB standards. This makes the documentation easy to read and the function easy to learn how to use. In fact you can simple swap out your calls to POLAR with calls to MMPOLAR to get started.
One interesting feature that Duane included is the ability to plot negative radial values. This is something to be aware of, because your results may look very different than what POLAR generates (which just uses absolute value).