There is no dot pattern. I don't know the methodologies others are using, but I'm in unidirectional 16 pass mode using Qimage and re-printing wedding prints I already did on my Epson R1800 on the IPF5000 and the IPF5000 pics look just as smooth even examined as close as you can get. This is true whether I print on Epsons premium luster or (what should tell if there would be a difference) on Epson Photo Glossy.
In addition, the color range difference is quite noticable in the shadows or in greens and blues not even in the shadows.
I printed some lake tahoe shots I did 2 weeks ago on both printers and they are just outstanding on the Canon. All the pics I've been printing where I've printed before, lay people and my graphics artist son prefer the Canon.
I have not played with the lower settings or bi-diretional yet to see if I can modify my workflow to produce dots. I'm not in a hurry anyway. I just wanted trouble free printing with a lower per page cost and a wider gamut. At this point, I'm getting exactly what I wanted.
My roll feeder addition is on order. I still can't print borderless yet. Also, the printer driver requires some careful print paper choices or the driver will not let you use the cassette tray, but that's just a learning curve issue and then a re-profile issue once you find a paper type that works.
Gone are the cartoony greens and the blues - just outstanding.
Here are the two specific pics where I noticed quite an improvement over what I had gotten from the Epson (and both printers are calibrated the same with Eye-one):http://www.fototime.com/3E8A57AF6B5A338/orig.jpg
(that's the ones where the greens look very cartoony on my Epson R1800)http://www.fototime.com/03E002F1A9A2CBC/orig.jpg
that's the one where the blues are outstanding on the Canon
Sorry - both pics are sRgb online. Printing aRGB on the Canon look better.
(edited to fix broken picture links)