Hmmmm, interesting to read all these reports.
A couple of notes:
1) I've used MIS ink for years, I have 5 printers, it doesn't clog any more than any other inks including Canon. Anyone who blames this ink for their problems- well, this hasn't been my experience at all, its been a wonderful product for me. Colorbat ink had the same reliability. I've bought brand new Canon carts that failed- so there you go. And I don't work for ANY ink company.
2) Prevention is worth a pound of cure. I say this on my ink web pages over and over-- print one good print a day, a test print, or every other day. This will keep your printer working. Let your printer sit unused for any length of time, you are asking for problems. That's just the nature of MICROSCOPIC nozzles. Accept the reality. NEVER let your printer sit without carts in the head-- even if they're empty. This reduces drying of any residual ink in the head.
3) I just got a "broken" i960 in the mail-- the owner could not unclog the head. I did it in about 7 minutes. Soaked the whole head in denatured alcohol for 5 minutes, then ran hot tap water through both sides of the head (bottom and top) for a few minutes-- voila, it worked perfectly on the first print I tried.
4) Most often, a "clogged head" is really a cart that is the problem. If you refill carts, this is extremely likely, if you don't, defective carts are not that uncommon- one that has been working fine for a while and that has plenty of ink- all of a sudden refuses to flow. Always try a different or new cart. All brands do this to some extent. I recently tried Arrow brand carts, 50% of them failed after a short while.
5) I have dismantled a print head-- this is an extreme measure, and does not guarantee success, so only try this as a very last resort, frankly, I've never had to do it with 5 Canon printers on which I've used for thousands and thousands of prints- all the methods above were enough. YOu can also break the lectronic ribbon connected to the nozzles- and this can not be repaired- so be EXTREMELY careful if you feel you need to do this.
Well, that's my 2 cents.
http://www.neilslade.com/Papers/inktest.html