Minor annoyances ahead.
I received the notification from Windows Update that Windows 11 was ready for my main computer. The basic upgrade process took a little less time than a feature update for Windows 10, and the only thing telling me that something changed was the time displayed in the upper center of the lock screen in a different font.
First login after update took a little extra time, but I kind of expected that.
Start menu and all pinned icons on the taskbar are now in the center, live tiles are gone in the start menu, and a bunch of apps that I'll never use were pinned. A few minutes of maintenance and most things that I use are where I can find them. If something's not pinned to the start menu, the assumption is that you'll either use a button called "All Apps" to reach the normal scrolling start menu, or will use the search bar to type the name of the app to find it fast. While I'm used to doing that at work to launch things like regedit and the computer management console, it's not something that I'd assume most casual users would do on a regular basis.
Most programs have worked properly so far, with the exception of Handbrake. It had helpfully offered that there was an updated version, which I downloaded and installed, only to find that it's apparently hard-coded to look for a specific version of .Net that's been replaced in Windows 11 with a slightly higher version. The upgraded program wouldn't launch, but reverting to the old version worked fine.
It took me several tries to fix the audio output for my computer. Windows 10 had a very simple selector that was directly available through right-clicking the sound icon on the taskbar. Windows 11 sends you to System\Sound Settings, where you have to tinker with the audio for a specific sound output device (in this case, an A/V receiver), and reselect the speaker layout. It took me a while to realize that the system defaulted to stereo if the sampling rate was set to greater than 96kHz. This probably wouldn't be an issue for most users.
Right-click menus in File Explorer have replaced the Copy, Cut, Paste, Rename, and Delete commands with a small icon ribbon that appears semi-randomly either at the top or the bottom of the menu. The items are just different enough from what I would expect that I need to verify what the button does from the hover text description before selecting.
I'm suspecting that there's a lot of precaching going on for programs, as most common programs load very fast. PowerPoint loaded in about a half-second, and Excel just a little bit slower. This computer's a newer gaming rig, though, so it's probably close to the top of the performance curve for Windows 11. The only other device in the house that will officially run Windows 11 is my laptop, but it has a smaller SSD and half the RAM, so I'm guessing that it won't be quite as responsive when it's finally upgraded.