The only reason, in this day and age, to have a custom model is to have a consistent trouble free fit every single time. The universal stage monitors have really propelled themselves to such a high quality and reproduction level that the only advantage is the custom fit over just using a universal monitor.
I am going the custom route because it's gonna cost me $156/year just for tips alone given the frequency with which i use my headphones.
You cannot convince me that any one set of custom monitors are worth over roughly $500. There's just no way. And just to start a flame war because i haven't trolled much lately: there is no sound improvement gained when changing cables from OEM to say, Dragon cables. None, at all, notta.