My pillowcase was a gift from Neero & Ana and it arrived beautifully packaged. The first night was a bit odd. I wasn't used to the slippery shininess. After about a week, however, I was convinced. Each morning, I awoke to hair that felt soft and my cheeks no longer had the indentation of pillow creases.
Deciding to be my own control group of one, I spent the last two nights with a cotton pillow case (600 thread, mind you) and woke up looking wild and woolly. My conclusion is that Satin Hydration Therapy is simple and effective. It's a must if you have dry, chemically-treated hair. The acid test? Yes, I would certainly buy one ($29 for a single standard).