Jim,
I'm sure you'll be pleased with the ATH50X.
A feature that you will notice is that they are more sensitive than cheaper headphones. In other words, you won't need to turn up the volume control so far to get a pleasing level for listening. Cheaper headphones often need the volume control to be set at maximum, which can lead the headphone amplifier to distort.
Try listening to Flingle Bunt with your new headphones. Brian's bass drum gains a whole new character with that extended frequency response - there is a rumble there that is very characteristic of the period, unlike the click/thud which came in a few years later when the technique was to take the front skin off and put the mic inside the drum. The rumble isn't loud, it's just there, where it isn't on cheaper headphones.
Ray