Actually, as a Certified Acrobat Engineer, I would have to disagree. If you create a PDF for the purpose of putting it on a website (it's called optimizing for web viewing) it will load faster.
The problem most people have is that they create complicated original documents and feel like they need to create them in high resolution. When creating for web viewing that's not needed.
There are a variety of different ways to accomplish your task without creating a PDF that bogs down the system.
The main advantage of a PDF is that it can be saved to a person's desktop and is a constant reminder they want to do business with you.
But what do I know...