I have bought from them 2 times in the past. Ordered some touch ups the first time and than ordered spray cans to repair a vandalized spoiler. The paint quality was great. But I do agree that their site is ugly.
For small rock chips, if you are planning to use the Kia paint pen, DO NOT apply using the foam tip that is part of the paint pen. Instead, pull out the foam tip and use either a thin brush or tooth pick to get a bit of paint and apply that to the rock chip. Apply at least two or three coats of paint before you apply the clear coat.
I initially made the mistake of using the pen as is for a very small chip and that left an ugly paint mark. Fortunately, the chip was on the front bumper and the touch up mistake doesn't show that much.