Last summer I wrote a program to compare two audio files, mostly to get an objective understanding of how sound degrades in a lossless format: http://andrewrondeau.com/blog/2016/07/deconstructing-lossy-audio-the-case-for-lossless
My conclusion is that, even at 320 kbps, formats like MP3 and AAC still screw with the sound. The newer Opus codec at 320 kbps is better than an 8-bit flac, though.
What happens with lossy audio is that it's more about "will someone notice an objectionable artifact" then "can someone notice the difference in an A-B test." Even then, the difference is usually in details that people don't pay close attention to. So, what you pay for in lossless is that the subtle echo in the fadeout sounds perfect, and that the equalization is always perfect, and that the cymbals and clicks of the guitar sound exactly like they do in the studio. Most people will never hear the difference, even in A-B testing.
In my very subjective experience, I find that AC3 has a certain dullness that lossless doesn't have. MP3 has a particular thinness that's noticeable compared to AC3. I personally don't have any opus files in my collection, so I can't comment there.