I started already. Here is a picture of the Mill Hill angel kit, all stitched up and framed.
I did cheat a little bit and started the Beginner Whitework Ornament, stitched with white silk on colonial blue 28 ct. Lugana.
At first sight the silk didn't look so much different from the cotton threads I normally use (standard DMC). But as soon as I started working with it I noticed the difference. It is softer, fluffier and shinier. It definitely feels more luxurious and natural to stitch and it is more random, if you will. Has more life in it, more character. At any rate, it is a welcome change from the good old cotton ;)