About 6 years ago I got the Shure E4c (the equivalent of today's SE425). I loved the quality of the sound, and of course the sound isolation was great for my commute on Chicago's mass-transit systems. The only drawback (other than the price) was that they broke very consistently. After almost exactly one year the wire began to tear. Not visibly, but you could hear the audio cutting out of one earpice at a time. I had them replaced under warranty, only to have the same thing happen one year later. Fortunately ths replacement pair was replaced under the 2-year warranty, but after this third set also gave up after one year, I tried something else.
I replaced those with the Westone 1. The sound quality is not quite as good as the Shure model, although it's still above average. Most importantly, after 3 years they still work great. I don't know if it's because they use the twisted cable, or if they're just sturdier, but they show no signs of cable tear. It's making me wish I had gone straight to a higher-end model right away, as I bet the Westone 3 or 4 has the sound quality more similar to my Shure E4c. The other great thing about those is that they use the same tips as Shure. I recommend Shure's black foam tips for the best mix of sound isolation/comfort.
Gordon had a good point though. Now they make these with replacable cables, so if you don't mind replacing the cable every so often, maybe the Shure's will work for you.
Sorry if that's a bit long-winded, but hopefully it helps.
