I got mine today and they are gorgeous.
However, the texture is pretty different from other MAC mattes.
They are thiner, made of very very small particules.
So, if you put some pigment on without blending it, it is extra bright and the more you add some, the brighter it gets.
But if you blend the neon pigment, it can get pretty sheer.
The orange one gets actually really light and I am thinking as using it as a blush.
To avoid the color to be sheer, the mixing medium doesn't work. The color then doesn't have the same shade everywhere...
I tried other bases, the best might be the white CCB and to avoid blending to much. Just pack the pigment on the base and will stick without changing color. Don't use a coordinate shade: fuschia for neon fushcia pigment, the pigment will look different.
My favorite of all of these new neon is the green one, it has a yellow hue in it. Unique!