I love excel spreadsheets, food journals, and other little "trackers" so for me MPF is just another fun tool that helps me feel more organized. I don't use their 'program' but instead customize my own numbers and just use it as a tool to count up my macronutrient ratios for me.
I have no issue counting calories in my little notebook, but manually counting up grams of protein, carbs, fats and fiber is a little too tedious, even for me.