The format is obj.

I do have good experiences with Zbrush and Vue together. Of course, high poly count will choke Vue, as said before. I managed to successfully import objects up until 700K or 800K polys.

To texture, I normally use one of two options:

After the object is modelled:

1. In the tools palette, texture group, activate "colorize"
2. paint your object with any color you like, how you like
3. when you're done, click on "Col>Txr", in the "Texture" group in Tools menu. This creates a texture with your paint job.
4. Go to Texture menu (not in the Tools menu, but the Texture menu itself) and click on Flip H. If you don't do this, the texture appears mirrored.
5. Export your object
6. Open the obj in Vue. Make the material a mapped picture and point to the bmp that Zbrush generated when you exported the obj.

Render and see. It should work.

You can also apply any material in Vue. If you want to apply several materials in one single object, one easy way is to create several polygroups in Zbrush (with your favourite method, there are several ways, see below my preferred). Then export the obj. This will come in Vue like an object with various sub-objects. To each one you can apply a different material (including bitmap based materials, of course).

The method I prefer to generate several polygroups in Zbrush is to mask, apply transparency, leave on screen just the polys that you want to be part of that group, click on "group visible" on the tools palette. Do this for each group you want to apply one material in Vue.