Both of them are good brands of domestic doors and windows. I don't know mercer. Let's talk about the Milan window for my home decoration. The workmanship is amazing. Glass is 4SG glass, which is UV-proof, heat-insulating and light-transmitting. It is warm in winter and cool in summer. The hardware is 4mm hardware, which has good anti-theft function and the sealing strip is welded, so it is not easy to leak. If you are interested, you can also learn about it.