I personally learned beginner Japanese using the Genki textbooks, though I think this is similar for other beginner textbooks. In these textbooks, they teach が to mean "but", as in "日本料理が好きですが、生卵が嫌いです。" However, when I was in Japan this past summer, I don't believe I ever heard people use が this way. けど was so much more common, and when people wanted to be formal, they used けれど or けれども. (I was in Nagoya, so it may be a regional thing.)
Why do textbooks teach が when けど seems so much more commonly used?