"The perfect cage" Hm, now that's a notion that I don't think exists. At all. And as Kyrilliondaemon said (wow! My iPhone just autocorrected "Kyrill" as Kyrilliondaemon without me asking!), anyways as I was saying, as Kyrill said, it tends to vary from person to person and ham to ham.
Personally I love the bin cages I have.
They're a little impractical in that they are stacked 3 high, and if I need to access the bottom ham I have to pull the top 2 off, but, it's doable. No big deal.
I sometimes wish I could have front access but then if I did Id feel I was just creating a weak point in the bin where a feisty and determined ham could make an escape.
I feel I've got a good balance between safe, ventilated and space saving