The Blood Type Diet certainly didn't work for me. I'm blood type A as well and do very bad on a vegetarian/vegan diet (bloating, nervousness, high blood pressure, etc.). I'm more of a believer in metabolic typing (I'm a fast oxidiser/protein type, which is just about the opposite of what D'Adamo advises for blood type A).
Read this review on the Weston Price website about the Blood Type Diet :