Quote Originally Posted by lord jackel
IMO being plastic they also hold heat better then the metal ones, and the enclosed structure makes keeping the humidity easier...but this is just my opinion.
Just to be clear to people that are just researching these products ... open air racks like Freedom Breeders are not meant to "hold" either heat or humidity (although, they do offer an optional alternate top if that is what you require) ... there are many many benefits to an open air caging system, but consumers must understand that heating and humidifying the room that the rack is in is almost always a must. For me, open air systems are the only way to go for ball pythons ... although I've had plenty of success using all kinds of caging.

Hope this helps.

-adam