I have used the sealed Gore system on my MTB. I liked the concept (which is very similar to Nokon), but the internal cable on Gores tends to stretch and never stops stretching. I had to adjust my cable tension about every third ride with the Gore cables. (The cable is black -- is it metal or some fiber?)

I went back to basic, Shimano Dura Ace cables. They last at least as long as the "exotics". They work. If you stretch them when you install them, they never stretch much anymore. They're inexpensive. And, if you replace cables once a year, like I do, there's no need for more expensive cables. Why spend four times as much for the same performance, except for the bling factor?