How PrimeFaces Stacks Up Against Other JSF Libraries

On many discussion forums frequented by developers, the question that crops up often is "if you were starting a Java Web project from scratch, what technology would you choose?" There are so many parameters involved in making such a choice that the questioner is usually either someone fairly new to IT or it is really just a leading question and they are waiting for an answer that will allow them to preach their personal choice (almost always one they profit from).