In fact there are some limits in 3D Coat not present in ZBrush :

-In 3D Coat, if you use Voxels and increase resolution one time only, it's very slow with big brushes

-Retopology on voxel model, even on low definition model, when you unwrap you can have : error message ont enought memory !
It has happend several times.
And caus i use it for doing real time models, you can't work if retopology can't unwrap, to bake normal map after.

To avoid the error you can divide your model on several parts , but when the model is in standard resolution, that is not very acceptable

Here is the simple model :


simple Retopology :


Because it happened several times, i'm somewhat confused wbout the tool.

Zbrush, is really really expensive, but with ZSpheres 2 incoming : it could be an alternative tool ?