I have a single crested in the exo 18x18x24 and she LOVES it. We have it stuffed with plants and I made a bit of a "junglegym" out of some random plastic thing from IKEA (design engineer, I see habitat items everywhere.) Two hammocks, a hide an a small tree stump round it out. She really makes use of the height and hops and flops all night if it is quiet. Nothing like the sound of glass doors shaking on impact! LOL

PS I got my exo online from... I think it was like Dr. Foster's or something, very cheap and they had great customer service when my original top screen was messed up.