Using MIS inks with iP4000

What's the general impression of the quality and reliability of MIS inks used in the iP-4000? Most forum data seems to be years old now but what's the story today, in 2010?

Are the stories about their pigmented ink ruining Canon printheads really true? Seems hard to believe. Will appreciate the general sense of the printing community.

Thanks,

DaveinFLL
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Pixmaker