With all due respect to canalphones (and I've demoed a few top Shures in various setups - unfortunately, UMs are not available in Russia, so can't firmly talk about those), I remain strongly convinced that canalphones, no matter how good/expensive/technically advanced they are, simply cannot sound as natural as supraural, or, more so, circumaural cans - by definition, for one single, but important reason: there's one extremely important acoustic element which is missing: sound reflection off the inner walls of the auricula. They might reproduce brilliantly articulated bass, refined mids, crystal-clear highs etc., but soundstage, airiness and natural sound are just not there.
This is in no way intended to raise some flame here, but it's a more or less physiological fact. For the same very reason no cans would ever sound MORE NATURAL than good speakers, and no speakers would ever sound natural to a live unplugged performance. The whole idea about GOOD speakers, cans, canalphones etc. is to get them sound AS CLOSE to live performance, as possible (does not apply for techno and electronic music, though). So IMO that's how close they've all got there: canalphones -> closed cans -> open-air cans (including electrostats) -> good speakers.
Having said that, I do admit that good canalphones do sound very good, but not as natural as cans.