There has been a fitness trend that favored sweet potatoes to white ones, mostly because they are richer in vitamins. The sugar is typically thought to give extra weight pushing powers and longer endurance.
Unless you are on a low-carb diet, you should be experimenting with both sweet and white potatoes and see which one you favor and which one gives you better results, to be franks, it’s all in your head. The difference between them is minimal.