Four-Way Ultrabook Battle: Dell XPS 13 vs. Microsoft Surface Book vs. Asus Zenbook UX305 vs. Lenovo Yoga 900 Dell, Asus, Lenovo and Microsoft all have Ultrabooks on offer. Here is a quick comparison of Dell XPS 13, Microsoft Surface Book, Asus Zenbook UX305 and Lenovo Yoga 900. by Sumit Passary