Digital BW, The Print

I have to soon order more inks for my Epson 4000 and I'm unsure as to  
which inkset to get.  I've been using the MIS UC Equivalent inks and  
refilling carts, but now there is also the "Pro" UC equivalent inks  
that I know nothing about.  I specifically asked MIS if the "Pro"  
inks have the new, no-bronze base and was told that the ink  
formulation was an "industry secret".  However, they did tell me that  
both inksets now use the same base - for whatever that is worth.  So,  
if anyone has used both inksets and can comment on the differences in  
performance (bronzing, gamut, etc.), if any, I would appreciate the  
info.