Digital BW, The Print

I have been using an Epson 1270 for my color prints, but am not 
satisfied with my b/w prints, using just the black ink. I gave up 
using the color inks. Too many color shifts. My question is: Should I 
trade up to one of Epsons' newer printers with the 2 black inks, or 
should I get a second printer dedicated for b/w printing only, and if 
so which printer and should I use MIS blacks or Piezography. I am 
looking for a neutral print.
Thanks: Jim