Isolated power (ISO) is a great stat, but it is limited. Power Factor both sounds cooler and is a better measure of a hitter's raw power.
There once was this dude named Wily Mo Pena. Wily Mo Pena did not play defense very well, he didn't hit for a very high average, and his plate discipline was pretty terrible. Fortunately, Wily had one skill that worked in his favor, and he used it to carve out an eight-year career in the big leagues: power. A microcosm of this was his 2011 season when he hit .