I find it very uncommon. I greatly appreciate the training that idols get in SK. (Yes, there is rampant abuse, but they are trained well). They sing in tune without autotune, their vibrato does not seem artificially enhanced (a particular hatred of mine as I am a string player). However, even with that PHS stands out. I am also a big fan of actor/idols singing on the soundtrack of their shows. In “She Was Pretty” Siwon, very movingly, sings the song of his character, a major plus….