Digital BW, The Print

I've been using MIS UT-2 inksets with Paul's workflows and curves in my 
Epson 1280 and am very pleased with the results.  I was wondering, 
however, if  -- flexibility of tone aside -- what the difference between 
a UT-2 and an UT-FS or FSN inkset is.  Are the resulting prints the same 
with regard to range and longevity?

Thanks,

Craig
Washington, DC