It's kind of unfair to compare the sound of the ER-4P/S to dual driver/triple driver designs. A single driver IEM will NEVER deliver the same bass that a dual/triple driver IEM has. I was also deciding between the E4c, Super.fi 5Pro and the ER-4P a couple months ago and decided to go with the Etymotics. I came from ER-6i and I was curious as to how the ER-4P might sound. I was completely dumbfounded. At first, the differences were slight, but as I listened, I was unable to stomach the maturity, smoothness and clarity of sound that the ER-4P had over the ER-6i. They were just that good!
I think the ER-4P/S has DEFINITELY achieved legendary status. They were created in 1997 and it has taken 9 years until anything (save the custom UE10/7/5) actually came close to threatening its reign. That fact alone, left me in a shock and I knew I had to get a pair. The design might not be the newest and latest, but that certainly didn't prevent me from getting a pair.
I don't think they are overhyped at all, in fact, I was dying to try what might be the most succesful IEMs ever. Their sound signature is very good. SOme say the highs are shrill, especially out of an iPod, but I have to disagree. How can you say they are shrill? The midrange is fluid and rich, the highs are detailed, and now the bass. Yes, they do lack in bass in comparison to the rest of the frequency range, but I strongly believe that a good source definitely helps. Straight out of a 4G iPod, the bass is indeed amaemic. Once put through an amplifier (from line-out), the bass does come out. Having said that, I don't think the bass will be loud enough for those bassheads out there!
Although sales may have gone down since it's golden years, I believe that they will remain strong IEM contenders. I urge those who are in the market for an IEM to try a pair. You don't have to buy a pair, just try a pair and see what you think. I admit that their might be better options out there, but whatever happens, they will still remain to be one of the best IEM ever made and I think that the word "legendary" can be used to describe its existence.
Now...forget the ER4, I want a pair of UE10Pro's!!!!!!!