sure they are useful, but to be honest, you can build one yourself WAY WAY cheaper than you could buy one premade.
I have heard very good things about them
all it takes is a watertight container of some sort. ie old aquarium, rubbermaid container of sufficient size, etc. some dividers that are held in place with silicone, and youre all set. Do some searched on here, but here is a pic to get started
