I received a sample of this in Buff and Nude. As my skin has yellow undertones, I was surprised that both of these shades blended into my skin extremely well. I noticed that the Buff color was a tiny bit more on the tan/yellow side, so I decided to buy it.
This is a very sheer foundation, but I wanted something a little less matte for the summer. I think it's a perfect summer foundation. Just beware, that because it's so sheer, definitely use concealor if you need to.
I use the Skinlights Custom Powders (in Natural Light, though I might switch to Golden Light for the summer), and I really like the effect it gives.