I assumed the same thing as you did, mouser. Anyway, I think it's better because in Directory Opus, you have the option of having it scan the size of each folder all the time, or by hovering your mouse over a folder for a moment. In Xplorer2, you just hit a hotkey and it does it for you. I like that more because this isn't a feature I tend to use very often, but when I do, I usually want to see the size of all the subfolders, and I don't want to hover my mouse over each item until it shows up, nor do I want to hunt through the huge options panel for it.