Honestly I have not seen much about that. ZBrush rendering is an odd thing and I dont Franky understand it.
However there are two main types, one is BPR and the other is Best, neither are what most people expect and both have idiosyncrasies and things they depend on.
For example:
Best will allow you to use things like Glow and Fog BPR will not
BPR will give you better (sort of) shadows and let you use BPR filters, I have no clue why those dont work in Best but they do not.
Best will let you render 2.5D stuff, BPR ignores (this is infuriating) 2.5D stuff.
Depth Cue is a total mystery, it used to be very cool.
The list goes on and on and then you hit differences like matcaps vs. lightcaps, I dont understand that stuff at all, you cant use both at the same time though as near as I can tell and that is another weird thing.
What I would suggest is trying stuff out.
What I do since I am totally baffled by how this stuff works and why it works that way is I turn on lots of stuff and see what happens, like this:

That is the setup I use for doing BPR renders, I think a lot of it often doesn’t need to be on because I’m not using things like HD Geometry, but I figure if I’m not using it ZBrush will ignore it, like if I turn on Fog or Depth Cue which do nothing at all.
Also in the render Menu in the BPR Shadow pallet I usually change the Angle slider to something higher, the last couple of ZBrush releases changed something and made shadows sort of harsh and low resolution and this slider helps soften that up a lot, I usually use somewhere like 11 or 22 cause they are easy to type and seem to get the job done.
I dont know if this is helpful or not and I am not the person to ask but I do know WHERE to ask and get far better (and possibly totally baffling) information:
http://www.zbrushcentral.com/forumdisplay.php?101-Other-Questions-And-Troubleshooting-Forum
I hope this is helpful!
Good Luck!