And we are doing well. Both came with teeth but I have reserved those for punishment. After trying both, the larger one is more comfortable for daily wear. We wanted to try this type of cage (started with Bon 4) before paying the big bucks for a custom one. The prison bird allows for better cleanliness and ease of urination without getting it all over the cage. So far we are happy. The mistress doesnt like how big the key is, it looks ridiculous on a necklace, but other than that, no complaints. We did use a hand tool to dull the sharp edges of the locking mechanism to make spooning at night more comfortable for the mistress. All in all, happy.
We didn't like the keys either, my avatar is the key I made from one by cutting it down and attaching it to an antique key. If you have a dremel, vice, and a drill, you can cut it down and make something a little more pleasant to the eye.
I cut the key down to length and width to fit the hole, applied some j.b. Weld, and let sit over night in a vice. Hard part was finding an old key with a heart that I could polish up. I did have to cut the old key down as well.
I'm currently looking at this devices as well (currently have a CB6000s). After few months are you still liking it?