I have been testing a sample of the Kat Von D foundation for a while now, and just recently got a full size. I will have a review coming shortly, but in the meantime I have some swatches for you comparing those two shades, which are the lightest two shades in the range.
The sample I have is # 44 and as you can see it is way too dark for me. So I decided to buy the full size in # 42, which they were out of in my local Sephora so I had to buy it without testing.
As you can see there is a HUGE difference between the two colors. I am really surprised there is no color in between.
42, 44, Jane Iredale BB Cream #1(for comparison):
I think I will have to mix 42 and 44 together to get a wearable color, otherwise my face is either going to be too light or too dark.
Besides the difficultly finding a color match I am loving the foundation though, and will have a review coming shortly.
EDIT: I actually ended up returning the foundation, 42 was too light and too pink, and so looked off on me, and I didn't want to buy another full size to mix with it just to get the right color. This foundation had amazing coverage, which was a huge plus, but it also ended up breaking me out. So unfortunately it was just not for me.