I had some issues with the update. First, the download process took a long while to finish. Then during installation it took while before a percentage appeared. Lastly when it got to around 30% my computer rebooted, but something when wrong and it didn't reboot correctly.
I had to force a shutdown and turn on my computer. This time the update continued after the 30% and finally finished.
I wonder why some users didn't have problems, like me, but others definitely have.
I wonder the same too. The issues I had were relatively minor, but some seem to report even bigger issues. I'm curious if the people that get those issues usually use some sort of software that disable telemetry and other services due to privacy, perhaps those software are messing with the way Windows 10 is updating.
Though the only way to know is if the people that get those issues also report whether they mess with the OS or not.