Intel's ultrabooks have well and truly arrived at IFA this week, with Acer, Lenovo and Toshiba revealing their entries into the new category of super-skinny laptop. The Aspire S3, IdeaPad U300s, and Portege Z830 all have their subtle differences, but at their core, they're machines designed for maximum portability with a minimal corresponding sacrifice in utility. Apple's MacBook Air is the gold standard in this respect, so we thought it worthwhile to see how well it stacked up against the Windows-equipped newcomers. Three Four galleries of detailed hands-on photos await your attention after the break.