I was using Nordost Red dawn speaker cable and upgraded to Siltech LS4-180 (the immediate predecessor to LS-180G3). There is really no comparison between these cables. Nordost is good for the price but the sound is slightly lean and the treble a little harsh to my ears. With the Siltech, all the harshness dissapears and you can listen at higher levels without fatigue. The strength of Siltech is the georgeous, detailed and airy midrange - basically detail with a hint of added warmth. The bass is also much better than the Nordost. As you go up the Siltech range you get more of everything but I dont think that the entry level cables get anywhere near the performance of the more expensive reference models which are significantly better .
I hope this is helpful. Incidentally I happen to be selling my LS4-180 speaker cable on Audiogon at the moment if you are interested !( I have changed to Transparent ref XL).