As a matter of interest, we have run Epsons, 9600s, 9800s, 9900s for 10 years now, and the clogging is a real issue, we have a guy watching each print with a spotlight to check for clogs. Silly, but its what we have to do. And yes we do have prints that start off fine and a third of the way a head just drops 3 lines of nozzles, ruining the print. If that happens in yellow you wont see it until its on a light table, which can be costly when printing on Hahnemeuhle Museum etching, if fact you might want stand in a corner and have a good cry, before composing yourself and trying again.
It's like I heard myself, I used to be the spotlight guy!
On the other hand the Epson dither pattern is superior, the fine greys and subtle highlights in skies and skin tones is just plain better and smoother on the epson. Its debatable whether its necessary, but when the client is selling a print for large amounts of money sometimes this is a serious consideration.
Just my two cents worth, but I am thinking of switching, I have noticed the Canon black is much deeper than the Epson 9900 on gloss media and just has a better "feel", you need to see the prints next to each other to understand what a densitometer cant tell you.
Im torn between the two, slight quality edge, vs no clogging, and we don't print on gloss media often.
I also preferred the Epson x880-x900 dither in highlights.
In my case it was easier decision - I'm printing a lot on baryta, pearl, and glossy media and love the "3D-look" feel you can get with the LUCIA EX inkset. I also like the fact, that the iPF is faster, and consumes much less ink than Epson (it needs maybe ~70% of ink for the same prints), and doesn't waste time and ink for MK<>PK switch.
Last but not least - I really hated that standing with the flashlight wasting time and paper, now my iPF takes good care of my Hahnemühle.