Customers of Cup & Cake Bakery in Cardiff highly praise the bakery's delicious cupcakes and exceptional service. Highlights include a wide variety of flavors, including vegan options, and accommodating choices for those with allergies and intolerances. The bakery is commended for its personal and timely service, often going above and beyond, such as adding extra cupcakes as a thank you to healthcare workers. The overall experience is described as fantastic, with many customers expressing their intent to return and order again.