Guide 2 builds your foundation clearly - it defines each arch systematically, lists bones/pillars/keystones in a consistent format, includes a comparison table (great for quick recall), and labels diagrams well. It covers the Transverse Arch more explicitly, adds Hallux Valgus and Club Foot (Talipes) as clinical correlates, and is much easier to follow on a first pass.
Guide 1 is best used after you understand the material. It's structured like an actual 15-mark answer - if your exam requires long-answer format (LAQ), practicing with Guide 1's layout will help you write complete, point-based answers. However, it has some typographical errors in the text (e.g., "Birobility," garbled sentences), so don't rely on it for exact wording.