I'll be the first to admit that I prefer store-bought anko. There's absolutely nothing wrong with that if you can get your hands on good quality, Japanese-made anko at your local Asian supermarket. Most Japanese brands of anko are well-produced and trustworthy. They have a pleasant sweetness, an earthy, delicate flavour, and are varied in texture. If you can get your hands on anko made in Japan, I would recommend it as it would save you some time and effort making your own anko.