I like them both very much. American blueberry is (when ripe) very sweet, like a candy almost. Bilberry (=blueberry to me) is very flavourful. Sometimes I want one, sometimes the other.

Bilberries really taste nice in milk for instance, or for flavouring icecream.

American blueberries don't add much to icecream, they sort of disappear in the general sweetness, but taste great on their own.