The one that was just described is the cheap one that basically looks like any other aquarium with vents on the sides....not worth any extra money to me. The other one is much fancier and comes in bigger sizes (I have a 36"x18"x25" one....you can get a 48"x18"x25" model though). These are typically noted for their molding to be sort of rounded, and usually a granite color. They have more vents on the sides, and come with covers so you can adjust how much ventilation. These one's are made out of tempered glass too, and they are almost sort of tinted just a tiny bit...just enough to make it a little better on the eyes than normal tanks. The tops are like the 3 section glass aquarium hoods, except the back section has vents across it, and you can buy the "heat and light" kit. With that you take one vent out, where ever you want the heat lamp, and attach the kit there. The middle section is screened and built specifically to support oceanic's flourescent lights.
I like the cage, but I'm still getting rid of it. It's would be better utilized for a viv or something. It just makes it too hard to get sydney (my adult beardie) in and out each day when the door is 36"x5". Some people swear by them though. I sort of wish they had devised a way to just use regular clamp lamps with them, but I've seen what happens when you put a hot lamp over those glass tops. I think those are probably the main design flaws.