Is a taller or longer tank better for an iguana?

Uhm YES a bigger cage is alwayss good. An animal will grow bigger in a bigger living space. Have some trees, vines, & an atleast 24x24 water tub to swin in. They LOVE to swim. My cage is about 4x4x4. Four deep, four wide, four feet tall also. He is not even a HUGE iguana. Godd luck with your cage search. I dont suggest a gl cage.