I gave my best not to give less than four stars to any of the beaches, but I simply couldn't do it with this one.
First thing first - I would not call Gerontas beach at all. The strap of sand is soooo tiny that if you lay down, half of your body will be in the water. :)
The rest of it behind are some rocks on which you cannot sit. Five people are way too much for this place.
Second, expect to see young naked/nude people there. For some reason, they find it the best place to go there, have "fun" and take photos of each others' naked bodies. And you are all over each other.
The road to Gerontas is, well, funny. A lot of bumps, not completely safe for normal car, but you could go there by normal car without consequences. Just drive slowly. The road goes up up up, then several crazy turns and so on. Pretty wild but ok.
At the end, you have to walk down a little, up to tens minutes, through not very comfortable terrain. For me it was nothing, normal slope and rocks, but someone who never walked in a wild nature could find it ouch, especially for thorns.
The only nice thing is the view over the open sea, because it's nice.