The Ultraboost's reputation is built on comfort, primarily delivered by the exceptional BOOST midsole. It provides a uniquely plush yet responsive feel underfoot, effectively absorbing impact from concrete and cobblestones. During my own 28,000-step marathon through NYC, the cushioning was genuinely impressive – my feet felt significantly less fatigued compared to previous trips using other sneakers. That famous BOOST "bounce" isn't just marketing; you can feel it helping you along, especially towards the end of a long day navigating from Central Park, over the Brooklyn Bridge, and back through the sensory overload of Times Square. It made a huge difference. However, the Primeknit upper, while soft and adaptive, creates a very snug, sock-like fit. While this feels secure initially, I found that after 5-6 hours of continuous wear, the snugness became constrictive, leading to pressure points. Many users echo this, recommending sizing up half a size and noting they might not be ideal for \*all-day\* wear if you prefer a looser fit or experience significant foot swelling. My feet definitely appreciated a break after a full day in these, more so than with some wider shoes.