I use Rayno and the Charcoal color for the S7 and S9 is due to the higher levels of ceramic vs carbon. I sell mainly S5 which is the deep black color, still has great heat rejection though. The S7 I typically only order if they are out of s5, the s9 I order for some higher end customers who prefer higher heat rejection. I wouldn't say the s9 is higher quality its just different film. If you message me I can send you some pictures