Very fun! We went a few years ago in April and it was gorgeous. Really was 4 seasons in a day as they say. Hot and humid, then cool and rainy. The hike itself isn't very strenuous, although the trail was washed out in some places and we had to take a detour, but it was still loads of fun. This was awhile back though, so it may be fixed by now. There were two chances to take side trails: one down to a beautiful beach with large cliffs, and one up to a cross overlooking the ocean.
A great, not too strenuous hike with nice views. When we went, the trail was pretty flooded. In winter, it can sometimes be closed due to bad weather, so be careful about when you do this hike. But overall, though freezing, it was a great experience! We went from Greystones to Bray, but you can do it in either direction (or round-trip, though if you're taking the BART out, you might as well do it one-way because you can take the BART to one end and pick it up again at the other). Loved it!