ooh, etys and sr225s... I didn't spend a very large amount of time with the SR225s at the so-cal meet (was spoiled by RS-1), but I did get a good sense of what they are like.
To answer your first question... very good. The etys will sound great, no matter what you're comparing to (well, i haven't heard omega IIs or HE-90s, but from everything else, they still sound great). The entire frequency range is crystal clear in the etys. Nothing is abrasive or obtrusive. There is no midbass hump to piss you off, and no treble spike to split your eardrums in two. They are neutral, but it just makes you realize how good music can sound, instead of realizing how goofy you can make music sound.
Etys are great phones for at-home rigs, as long as you aren't bothered by the fact that you can't hear anything while using them. They sound great, are immensely comfortable, and can easily be put in the little pouch for portable use.
As to how they sound compared to each other... Austonia explained it well when he said they are two different beasts. (not sure why he used the word beasties, but i will refrain from repeating it) I thought the etys presented a better sounding scale, but that's always personal. The sr225s definitely had stronger bass impact, but that's what makes grados grados. Etys were definitely clearer, airier, and whatever goofy words you want to come up with, except for punchier (if that's even a damned word). The grados are phones that make you say "hey, nice impact" or maybe, "these are a bit bright, but i can handle it." The etys are phones that make you wonder, "What? why do these sound so damned good?"
I hope that helped.