The 272 would have to be one of my favourite IEM's ever. To get the best out of them I prefer it amped.
The detail these things have is nothing short of outstanding. Bass is quick well defined and refined.
So if you like your bass in ya face....not for you. These are about quality not quantity. Only negative for me was I found the tips did not suit my particular ear shape, so getting the right kinda seal is always fiddling about for a while, but once found and then paired with a decent amp you forget about the hassle.
The 272 is special, Its a sure shame they stopped making these.