I've been using the AOC U32G4U for a few weeks now, having upgraded from a 32-inch 1080p monitor. Especially when gaming, you immediately notice the difference 4K makes. Games look sharper, and small details are much more noticeable. The color reproduction is beautiful and looks natural, without the image becoming too bright or unnatural. A big plus for me is that I don't experience backlight bleeding. With my previous monitor, it was clearly visible in dark scenes, and it often bothered me.
The 160 Hz refresh rate in 4K feels very smooth and makes fast movements easy to follow. I tested the dual mode with 1080p and 320 Hz, mainly out of curiosity. It works well for competitive games, but I found myself quickly switching back to 4K. Once you get used to that sharpness, 1080p simply feels less comfortable at this size.
It's worth noting that the monitor doesn't offer a true HDR experience. It supports HDR400, not HDR600, which limits the difference compared to SDR. Furthermore, the monitor doesn't use a joystick for control, but rather several separate buttons. This works well, but is slightly less intuitive than joystick controls. All in all, I'm very satisfied with the performance and image quality.