The level of clarity and details on these canalphones are much better than traditional headphones. Partially due to the isolation, partially just because the driver is able to reproduce finer detail. I think the level of detail might only be rivaled by electrostatic headphones, but I never tried a electrostatic, so I can't say that for sure.
I can say for certain, out of all the traditional dynamic headphone I've tried... nothing comes close. You do spend a huge amount of premium for the miniaturization though.
On these multi-driver canalphones, even the sound spectrum reproduction is fulfilled, unlike the single driver canalphones. So that's not a problem either.
The only thing that full-size headphone will still, and probably always, have an advantage over these canalphones, is the soundstage. You just can't get that soundstage "outside of your head". However, it's an effect that I've gotten quite used to, and makes next to no difference to me now.