The shores of Rosh Hanikra are a complete contrast to the rest of the country. Here you no longer have the immense beaches that remind you a bit of the south of France. The cliffs are king and it's impossible to swim. So if you are going to Rosh Hanikra it's more to enjoy the scenery than to go swimming.
Once you are there you will be amazed by the rocky formations which aren't found anywhere else in Israel. I also liked the fact that you can still see the line of the railway which linked Cairo to Istanbul, so you can take a moment to imagine what a peaceful Middle East might look like.
However, despite its attractiveness, I don't think Rosh Hanikra merits being the sole object of a trip. It's more somewhere that's nice to go if you are already in the north of the country during your trip to Israel.