I was one of those developers with an OS X machine who decided to buy a Thinkpad and throw Ubuntu on it. pulseaudio worked out of the box for me and I definitely preferred it over the stunted OS X audio mixer that doesn't even let you define per-application audio.
The MacOS mixer is pretty much the epitome of "just works" even though I agree with you that it doesn't let you control levels per application.
However I've been using the MacOS sound system (not just the mixer) for many years through many devices (mics, external dacs, HDMI transports, DP etc) and it has always worked without any problems.
I don't have much personal experience, but I /often/ hear about OSX users very wary of updating MacOS because of issues with sound equipment. This goes back to Classic. It may have gone away in the past 3-5 years, but the stigma is still there.
