I received my copy of Aitchison and Hey last week and have nearly finished reading the first volume. So far, the text is living up to its legend: it is very readable, well cited (so the historical context can be reconstructed) and pitched for a graduate student who has seen the topic before but is looking for the kind of "handle" on the subject that is missing in nearly all other volumes on QFT (esp so Peskin). If you are struggling with your first look at QFT, reviewing the subject or trying to get a headstart through self instruction --- this book is essential. I would strongly recommend that all physics graduate students read this text after completing the usual third semester grad course in QM that often includes a first look at relativistic QM, KG eqn, and Spinors. I would also recommend that one begin by just READING the book carefully before trying problems. Aitchison and Hey have created a very reader friendly intro to QFT and the standard model that is not watered down.
Take my advice: start reading this book in parallel with your QFT coursework or beforehand if you can. These books are worth every penny and every minute of your study time. Many mysteries are resolved! Enjoy.