What does the Cage feature do in the sub-division area?
And when you reply please add a little more info then the standard, blah and it blahs.
I think I understand that a cage is a representation of a high poly thing that you can take to a low poly thing, or perhaps I have that backwards???
So I appreciate any insight that you might have…thanks so much! 
http://www.pixologic.com/docs/index.php/Tool:Geometry_Subpalette
Cage: When turned off (the default), edits made at high subdivision levels will also displace vertices at lower subdivision levels. This is usually the best way of doing things, as it gives the smoothest and most predictable results. When turned on, ZBrush will attempt to keep lower-level vertices from moving as higher-level edits are made.
Cage is meant to be used when you’re creating a displacement map from a model that was created from scratch in ZBrush and so never had an unsmoothed cage version. For example, if you use ZSpheres to create a model, that model will have multiple resolution levels from the start. There was never a level 1 that had not been affected by multi-resolution editing rules.
Cage meshes are very important with displacement maps since disp maps are calculated under the assumption that they will be applied to a cage that will then be smoothed by the renderer using Catmull-Clark algorithms. To get an accurate displacement, you therefore need to have a cage mesh to apply that map to.
When you import a model into ZBrush, that original OBJ is your cage. You can store a morph target before dividing the mesh. Then when you return to level 1, the multi-resolution rules dictate that level 1 will have been affected by the changes made at higher levels – including the contraction that took place when the model was divided and smoothed. Now you simply switch to the stored morph target to restore the original cage before creating your displacement map.
If you didn’t store a morph target before dividing, you can instead store one when returning to level 1. You then import your original mesh again, which restores the cage mesh so that you can create an accurate map.
But as mentioned earlier, some models never had a cage to begin with. That’s where the Cage button in ZBrush comes in. You turn that on so that ZBrush can calculate a cage that would subdivide to come close to the high res version of the model. You then create your displacement map and export both the map and the OBJ cage.