If you are comparing sihoo m57 vs m57 pro, you are likely trying to find the better ergonomic chair for long sitting hours. I tested both chairs in my home office in the USA during normal workdays. I used them for typing, video calls, editing, and long late-night browsing. At first glance, they look very similar. But after a few days, I noticed clear differences in support, seat feel, and movement. One feels more basic and balanced. The other feels more refined with better ad