I think you are confused, uber indicates extremely good(actually, ultimate)- these headsets are both what you call 'low end crap'.
In terms of the reccomendations for Sennheiser- they make everything from $8 low end crap to $2K can/amp combos. You may have heard about crappy Senns, there is no doubt they are out there, but they also do make what can arguably be called uber headphones.
You want a setup for gaming, do you want sealed or open? Comfort is a concern for you(ruling out Grados), but what factors are the largest elements- fit, weight, padding? The cans you listed both are driven fairly easily- is this something you are concerened with more then sound quality?
Wow $700 headset? They may sound good in a cockpit, but how do they sound playing your favorite mp3's?
Hook them up properly and you will very easily hear the limitations of your MP3s. You really need a lossless codec for a high end setup(of course, not like most small aircraft has a decent audio setup anyway

).