The HDMI pretty much just works. Even at 8k resolution. Note that last I checked, Monoprice's DisplayPort cables (as opposed to HDMI) only supported an older standard and they don't handle 8k. Most of my monitors are 4k though, and the DisplayPort cables work fine for that.
USB can be finicky. Sometimes certain devices, or plugging and unplugging devices too much, can "crash" the USB cable, requiring a "reboot" by unplugging it and plugging it back in, from the computer end. But if you're just using a keyboard and mouse through it it's basically fine.
Very occasionally one of the monitor glitches out for about 5 seconds (maybe happens about once every 2-3 months), and they both seem to take much longer to wake up from the lock screen, again in the order of 5 seconds. Other than that had no problems whatsoever, and definitely the sound is much reduced. I only hear it at all when the GPU is maxxed out, and it's not unbearable like it is when it's right next to you. 4 years ago, the cables were £9 each for 5M DP M-M and £10 for the 5M active USB3 cable, but it's pretty cheap for the quality of life improvement.