...of the 'phones in question.
I first bought the 125s because I found I had some extra cash in my pocket, so I traded up. WOW, what a difference (the sound you're hearing now). Then I said to myself, "well, if there was that much difference between those two steps, I'd be willing to pay another fifty for the next step. I did get the 225s and I did not regret it. I am not ultra-rich, but the difference was worth it.
The difference was that the bass felt much more "sorted out" and less of a muddle with the mids. To me, it was worth the fifty dollars.
The only other higher model I've heard (which I now own and have experience with) is the RS-1s and I must say that I am enjoying the sound of these cans even more that the 225s and below (I've owned from the 80s on up, as described). The most wonderful thing to me, so far, is the absolutely holographic soundstage, which really does the trick of putting one "in" the recording. This can be altered depending on your equiptment, including the cables you use.
As everyone has said so far, it is a far smoother sounding phone, a very pleasing difference to me. I can't say I was 100 percent pleased with the 225s, as they were revealing of the "digital edge" on CDs in a not-terribly-pleasant way. But were talking minutia here, especially if you're relatively new to all of this.
I would say your best bet is probably the 325s, based on what I've heard. They're top-of-the-line in the SR series (you can pride yourself on that) and from all reports, they sound great. Plus, they've got that kewl metal look which I'd go for in a second if I wanted a second pair of cans.
- Matt