No, voxel count + polygon count affects performance. In Zbrush, you are only worried about polygon count. If you want to compare apples to apples, don't add the voxel overhead, compare teh two when using only polygons. The mesh shown is only a proxy of the underlying levelset surface. The SDK allows you to export this array to your rendering software so you can render the levelset directly. Zero polygons.
So using voxels will always be vastly less efficient vs regular polygonal methods in terms of overall geometry achievable on current hardware?
Like my suggestion of an option to remove the polygonal skin from the voxel room and work directly on the levelset (as i understand it there are several alternative methods of smoothing a voxel volume that don't use a polygonal skin), would this be more resource friendly and allow us to work at an additional subdivision level than is currently possible?
This is exactly the stuff i am trying to find out, i realise voxels have many advantages but if we won't be able to get much finer control over surface details at some point i think it's important to know this in advance so people don't get their hopes up too much. If voxels will be limited to mid-high frequency details, with the final touches being done in Paint room or another application then i can live with that, i just want to know one way or the other what's going to be possible in near future with the voxel room.
For me the idea of working on a model from start to finish (including painting when Andrew implements this) entirely in voxels is very exciting, but the overall geometry needed for fine detailing is just not possible at the moment.