We do hear things differently, and that's quite normal because we have different earcanal shape which is like a filter for the sound traveling from a tip of the nozzle and through to your eardrums. I only tried IER Z1R for about 10min at the last year canjam, driven from WM1Z and I was overwhelmed by a piercing treble (and I tried different eartips). Someone told me those need a more powerful source, but to my ears while I absolutely loved the bass, upper mids and lower treble were piercing and harsh.
For the reference, Crin's measurement of it. The energy of 6k sibilant peak was just overwhelming to my ears and there was just too much crunch in upper mids around 3.5k-4k.
But all this means that it wasn't for me, while I know so many other people who enjoy it. And also a good example, you can't base your decision on one person's review because in some cases we could have a polar opposite opinion
and the same with Cupids, our ear anatomy will dictate the comfort of the fit.
For my ears, I found the design to be quite ergonomic, fitting my concha area like a glove, though extra weight could have some effect on the comfort.