In general I think cockrings are great! Certainly makes most cocks even more pleasing to the eye.

I like the leather ones with the studs so you can vary the size, plus it's easier to gauge which one to buy. As for those round metal ones, you'd have to know your size and I don't think they will let people "try them on for size" in the sexshop. I've heard of people having trouble getting them on and off? I actually got a very small chip off one tooth from one of those wretched metal ones when being throat fucked....
