You can't judge a piano method by its exercises; you judge it by its repertoire. Grade 2 features a mix of folk songs, classical themes, and original compositions.
At the top of almost every page in the Michael Aaron Grade 2 book, there is a 2-bar or 4-bar exercise. These are not "warm-ups"; they are the DNA of the piece below them. Play the exercise 5 times slowly before touching the piece.