I bought these lines two months ago, wanting to try a different brand. They are expensive (I paid £27 for 2x35m@75kg, yes I know I could have got them much cheaper on Bilbo but I like to buy a couple of items a year from my local kite shop) so I expected good things. The lines are extremely smooth, and reminded me of LPG, thing is I don't like the noise that LPG makes when twisted under tension - it is only a little niggle as they are good lines, but the creak offends me. I was delighted to find that Skylines make no noise when twisted. One other problem that I have had with LPG in the past is the sleeving loosing structural integrity and becoming all bloated and unable to hold a larkshead. The Skylines have not had this problem yet. Having now been flown in strong winds, they haven't shown any stretch difference and no correction has been needed as yet.
There is one problem with Skylines though, and that is their winder. I do not know which imbecile designed it, but the geometry of the winder means that it will not unwind if you pop your thumb through the hole and pull the lines off... you need to manually tip the winder up and down for the lines to come off. I immediately put them onto a Climax winder, but still, I find it amazing that such a simple device could be designed incorrectly.
Of course, the most important thing for lines is longevity, as they really are pricey. I'll update this post when I know how they fair.
- I'm pretty sure it's possible to construct convincing arguments either way. 
