I agree that there is no correct way. Having said that, I use bags because they reduce the chance of a stuck transfer and lower the sediment in carboy. If you ever consider a plate chiller, you will want to transfer the clearest wort possible (to prevent clogging it).
I think there is nothing wrong with a 'muddy' wort, but a clear wort lends itself to simple transfers, which speeds up the day, which leads to less cursing, and more happyness. So I put hops in a bag.