Digital BW, The Print

I tried to employ MIS cartridges on my 1290 EPSON printer in order to 
have a quality B/N printout. I received two sets one QFS and one QVM.
The QFS one has the black cartridge not recognized by the printer 
driver, the QVM one after five printouts (quiet good) seems to be 
empty even if the level displayed is at 75%! MIS e-mailed anwers that 
they can change the products.
Does anybody have had such experiences with MIS product?
Is MIS product a good choice for B/W quality prints?

Thanks for an answer.

Corrado