In fact for me it's fast.
And in Zbrush also there is a limit , even if it is lot more far.
In 3D Coat, you need to bring the general forms before increasing resolution and putting details.

The last version seems more faster , and really faster in terms of Booleans between objects.

One important thing is when you are in high resolution , to use the surface tool that is indeed as fast as Zbrush tools caus it works on surface not on voxel volumes

So the workflow can be that :
- Voxel mode , and Clay Tool : Build the basic shape
- Increase resolution : continue with Voxel tools
Fix and finish all definitive shapes.
At this stage you can mix Voxel tools and Surface tools
- Increase resolution and use surface tool only (or Voxel
tools with tiny brushes), to work on surfaces and bring
high details

The Surface tools are what allows you to work faster, and you can mix Voxel and surface before going too further in resolution.

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For Zbrush, indeed it is really fast, and Dynamesh tool allow
to bring corrections and make an uniform triangulation like Clay Tool in 3D Coat.

After testing again the Clip tools and Dynamesh, hard surfaces
on Zbrush is easy and fast, and Dynamesh brings also big creativity. And in terms of speed Zbrush is unbeatun for me

What Zbrush lacks is big retopology tools. That's one main point that makes me stay with 3D Coat.
So my workflow is lot more now :
-Zbrush Sculping
-3D coat Retopology
-3D coat normal map making
-3D Coat Texture painting

Well ... after that it's a matter of taste and project type !