MacOS 🙂 I have been using an iMac 2015 5K display everyday for hours at a time. I just leave it on and put it to sleep. No fan noise, just bliss. One piece computer unit, built in display and speakers. No more " blue screens" and wasting time and money in repairs and issues configuring software or devices for me. I also have setup seven desktop spaces with different apps running on each one that I can scroll, switch, to. Apps can be assigned to different Desktops. Each Desktop has its own background. Another nice feature is that I can shut down the computer, restart it and continue where I left off without having to reopen the apps and files. It does it for me.