Digital BW, The Print

I was just on the MIS website.  Their prefilled spongless cartridges 
for the epson 2400 is $98.55.  The original Epson cartridges at MIS 
cost $114.00.  Does anyone know if the spongless carts from MIS hold 
more ink?  Are the inks significantly different?  The cost 
differential is simply not that much to warrent the MIS inks if there 
is no difference in volume or performance (I know, what do I mean by 
performance)!

Thanks in advance

Joe