Grado Prestige Series phones upgraded with the G-Series cushions are long-term awesome.
There are several Prestige Series models...and prices...where you referring to any one model in particular?

Also...the upgraded G-Series cushions...do you get them with a particular model, or was that a separate purchase after?
I've been wondering about a new pair of phones, just for my studio use for checking mix issues, etc, not for tracking use.
My current go-to phones for that are the Fostex T50RP MkII, semi-open back model. I have 3 pairs of them, and also a couple of pairs of the T40, which is closed, that I use for tracking, but I like the T50 sound much better, so I took one of my T50 phones, and made them closed-back...simple mode with some gaffer's tape inside the cup, just to cover the open slits, which is how the T40 are "closed", the slits are covered.
Anyway...I've looked at some of the Focal phones, and the real good stuff is way pricey...but would like to have something else besides my T50RP for mix checking.