If I can interject, the suction cups that are supplied with the Riparium Supply planters are made of a thick and flexible plastic and they hold much better than the ones used for most kinds of aquarium equipment; they really do. So long as you keep the glass and the suction cup pretty clean and keep plant roots out of the way they will almost never fail. These suction cups last a lot longer too. I have observed them still holding well after more than two years.
I mean.. i use shower caddies, but the biggest thing is if youre going to use the non riparium supply ones, you need to get hold of expanded clay pellets. Other beddings are going to be too heavy and fall. or you can do like me and do suction up AND wire hangers. Im just a cheapskate though heh..so...