Digital BW, The Print

I went to a camera shop to buy a 2400, but their printing "expert" said some 
things that gave me pause; questions I'd like to pose here:
1. He said you can't get a good dmax using the Epson inks on matte paper. If I 
wanted deep blacks, I'd have to print on luster or glossy papers. Is this true? 
Are others getting rich blacks with the Epson inks? If so, are you doing it with 
the ABW driver or having to use QTR?
2. He had heard of people using MIS eboni instead of the MK, but warned that 
if the print head failed, the warranty would be voided. Has anyone had a print 
head fail? Wondering how often this happens and how others have handled 
(rationalized) this risk?

Cheers,
George Le Masurier