Digital BW, The Print

I was considering switching my Epson 4000 over to MIS UltraChrome 
equivalents, mainly for cost savings.  

Is anyone using these inks in a 4000?  If so, how do you like them and 
how do they compare to the Epson UC inks?

Do you buy the filled cartridges or refill your own?

Any clogging, Dmax, color gamut, or other issues?

Any fading or permanence problems?

Any final words of advice or caution?

Thanks alot, 

Lou