I was able to find a comparison between ZBrushCore and ZBrush on their website.
Sadly, by the looks of it, there will not be the ability to create 3D layers. ZBrushCore is pretty much just a clay modeling software. At least you can import/export in OBJ so it isn't completely isolated from other 3D software packages like Blender.
The upside is that if you decide you want to upgrade to the full package, you just have to pay the difference. The downside is that the difference is freaking $650.