Price doesn't impress me. However, quality of parts and more exotic configurations do correlate with price, and that can get you better sound quality when properly implemented.
For example, Yuin OK1 buds. They're uber expensive at $230. No normal person would in their right mind purchase such a product. In the grand scale of buds, it's an insane buy. Is it worth it? Does it actually provide outstanding sound? Yes. Yes it does. $230 worth? That's debatable, but relative to their IEM cousins and any other audio reproduction system, they do perform wonderfully and competitively within the pricing one commonly finds for a premium earphone. They have certainly been a favorite of mine.
It doesn't mean that an earphone has to be exotic or expensive to be good or that the exotic/expensive option will decimate the cheaper competition. For example, I'm very impressed with the ER4 and PFE BA IEMs. I'm just now getting into the top tier IEMs and testing them out, first the TF10 and now a UM3X on the way and probably a couple others like the CK100 and IE8 later.
I actually like the ER4 and PFE a lot for what they represent and what they are capable of doing at their price level. The TF10 does great in terms of frequency response because it has more drivers to cover the spectrum. A single BA is like a wide range driver, works over a certain area but can't really cover everything. The double and triple driver options are like 2 and 3 way component sets, easily covering the spectrum. The issue then becomes a matter of if the driver is actually better or not. A 3-way component set with mediocre drivers may cover the frequency spectrum well, but it will still end up mediocre. In some ways, the TF10 lacks some aspects of what the ER4 and PFE drivers were capable of capturing. There can still be issues with the driver or the implementation of that driver that can limit the setup as a whole. The TF10 doesn't entirely impress me even though it's a top level, triple driver (2-way) setup. It does do many things really well, and there really isn't all that much to complain about beyond personal preference. However it's also a technology premium and price premium that one begins to demand perfection from.
At 2x plus the price, one typically expects a significant leap. Then again, that's not really how it works. The leap is more logarithmic. You get great gains from super cheap to cheap, moderate gains from cheap to mid priced, and small gains from mid priced to high priced. That's just how it goes. By the time you get to the top end of the spectrum, you hope the end result is nearly flawless though. That isn't always the case. Even if you read reviews of all the top level IEMs, you will always see people complaining about various aspects. Personal preference wins out more often then price.
