I have used a silk pillow case for many years and absolutely love it. I use it more for a skincare and eyelash point of view (I have eyelash extensions and cotton cases tend to pull them out), as my hair is fairly manageable.
One thing I can recommend is getting one in a darker colour - a charcoal or black. I had a white silk pillowcase for a while but because of all my glorious serums it turned a funny colour. Whoops!