In reply to Mark Reeves:
This was one of my favourite days out back in the day when I lived close enough to nip over to Snowdonia for a day, back in the early 90s. Once you're a few pitches up, the convex nature of the slab means that you can no longer see the bottom, and there's just you and your mate(s) on this patch of rock half way up to the sky. The climbing is never difficult for the grade, just exposed, though if you do rope it, there were sections with little gear in for the more nervous leaders. It would take for ever if you put lots in though! Mostly its just wandering around near the edge of the slab until your rope starts to get heavy, then find a belay. Though easy enough, its highly recommended for anyone with a sense of adventure, whatever grade you climb.