i have a pair of P20,000 Shure earphones. its good but honestly, i opine a mid level headphone will beat it or at least be at par with it, sound quality wise. at the amount i paid for the earphones, i could have gotten a good pair of headphones. ....but i was avoiding the bulkiness.
a good modern earphone will block majority of the outside sound because of the seal even without noise cancelling ability. having the NC will boost it abit.
however, noise canceling phones will not block out everything. I've tried the top of the line Bose Noise Cancelling headphones. the sound quality is really good, but while inside the room, i could still hear the sounds from the street. nothing can be totally blocked. i think pwede naman bawiin sa "volume" but im not going to go that way again. id rather hear a bit of the street sounds that have ear damage in the long run. (not gona go there again. masaya na ako at i recovered.) but after testing the bose, i opine its worth having. ayaw ko lang na malaki at may cable. lol sana ma improve pa performance ng wireless.
noise cancelling can only cancel out repetitive sounds kaya it works well with the hum inside an airplane. it might work for the aircon but you might still hear a bit of hum when the thermostat allows the AC to "rev" up.