blue "run dry" impellers in your raw water pump? If so, are they that much better?

Like the one at; http://www.amazon.com/Globe-Marine-4528-0001-22429-0001-8293-0001/dp/B00C9L63UY/ref=sr_1_6?ie=UTF8&qid=1385438988&sr=8-6&keywords=yanmar+run+dry+impeller

Just thinking about it... wondering if it's worth the extra $. I change each year.

Greg