Update went trouble-free for me, and reasonably quickly too. I didn't time it, but less than 10 mins all told probably (not counting time spent downloading.) Did not notice any difference in the 30 seconds I spent after the OS booted back up...

Will see if I hear any chimes or such; had a few singular charger chimes over the course of a week and a half maybe, and then it went nuts, chiming multiple times over the course of maybe an hour or two, at which point it eventually crashed - which I only noticed the day after when I lifted the lid and it was black and dead and unresponsive. Booted it back up, and it had had its first (and so far only) kernel panic. (T2 related, although I did not examine exactly what had gone wrong.) This was over a week ago now, and nothing since. Not a single peep in fact.
So touch wood...
it hasn't fixed the constant noise in my headphone port which sounds like really bad shielding. during the install process, the noise (which is the same volume irrespective of the computer's volume setting) went away until the install was halway complete making me think it might be fixed, but no such joy.
If the issue is what it sounds like - IE bad shielding - then no software in the world will be able to fix it. That it went away momentarily is probably because the installer most likely shut down the audio sub-system/amp during the update. Then after activation it would power up the audio hardware again, and the noise would return.
Personally I've never been super impressed by Apple's audio hardware; my OG Apple Watch's speaker hisses extremely audibly any time it plays audio, my previous MBP's headphones jack hissed, plus it popped any time the audio CODEC went in/out of power save mode (known issue for my generation of MB IIRC). My 2018 MBP's headphones jack also hisses, but then again I plan on basically never using it, or at least as little as possible, preferring the cordless freedom of airpods instead.
It usually gets pretty hot while doing things that i would't expect it to get hot while doing them. Like downloading a large file or playing a video on plex. And it feels like the fans are at full speed pretty often.
My experience has been pretty far from that, with the unit running silently and cool most of the time, although curiously, this particular software update made the fans rev crazy high. I've literally never heard them spin that fast before, ever.

Unit did not have time to heat up noticeably though, as it quieted down significantly after a one or a couple minutes.
I often had my old MBP spin its fan up to turbo speed though (2011 generation), and it had a really horrible, noisy fan, so this was not fun. 2016 onwards MBPs have a much better designed cooling system, from a noise standpoint, as the dual blowers used now are never anywhere as loud as the 2011 generation's single.