Dropping your bounce rate and having faster loading pages are good reasons by themselves to break things up a bit. However being able to track your traffic through your articles is an even better reason.
When you start tracking where people are dropping off or what parts of the articles they are skipping you can take that information and change they way your are developing your content. This leads to better conversions and more money.
How do you decide how to break up your articles? Do you do it by length or??
Also a lot of sites that do product reviews list the different sections so you can skip around to the parts you are interested in or all the way to the conclusion section. Is this something you do? I am wondering if a lot of people like to skip to the end.