Potato starch and corn starch are both effective for thickening and for use in baked goods. You will be able to use either one in most recipes and wind up with very similar results. That said, there are some differences between the two as each of them is better for some applications than for others.
If you are choosing between the two, there are a few important questions to consider. Let’s review in another SPICEography Showdown: potato starch vs. corn starch.