Sound is very important to me but not to the extent that I would make my car buying decision solely based on it. At the end of the day overall performance outweighs the sound for me as well (if it didn't, I would be driving an N55 M2 today). I wouldn't argue how good the N55 sounds compared to S55. The difference is pretty significant IMO. However, I think BMW did a good job on improving the sound of S55 over the years through several software updates and changing the muffler design on the Competition Package. It still doesn't sound amazing but much better than when F80/82 first came out in 2014. I have seen several companies (including some industry leaders) try to come up with various solutions to fix the S55 sound in the past 4 years and some of them provided real improvements (as posted above). My take based on all this is you can improve the sound of S55 but can never perfect it. It is what it is and I'm ok with it.
P.S. Here's how my M4 ZCP sounds on free revving with MPE (Sport+, no additional exhaust mods). Again, it doesn't sound anywhere near perfect but I'm happy with it and actually quite like it.