I spent a night on Crib Goch ridge last week. It was a great experience sleeping under the stars, and watching lights of llanberis down in the valley. As a bonus, there was a cloud inversion (more pictures to follow) in the evening that covered the whole area around Snowdon Horseshoe. It was mostly dispersed by sunrise, but there was still bit of mist/low level clouds down in the valley.
This is a 6 shot panorama of the Snowdon Horseshoe taken from Crib Goch. Some of the low level clouds can be seen behind Y Liwedd on the left, and beyond the descending ridge on the right.