I don't think you are going to see a difference on matte paper because the surface is too rough and absorbent for fine dot placement.  The new overdrive feature is good for lenticular printing, photo telescope keychains, high res line diagrams, pano (stitched) photos at relatively small sizes (one sheet), and other types of printing that require magnification or high precision.  Once you get to 600 or 720 PPI, you're not likely to notice an increase in print detail going to 1200 or 1440 (overdrive) just by casual side-by-side observation.  Close examination of sharp edges or details like tree bark though, even with the unaided eye, will reveal some differences with sharper edges and more detail on the OD prints... provided you have an image with enough pixels to begin with.

If you want to test out the new overdrive printing, keep this in mind.  You need enough pixels in the original image to render actual detail at or near the overdrive resolution.  Let's say you have a Canon or HP that uses 600 PPI as its native resolution.  And let's say you have an 18 megapixel dSLR (pretty good for today's mid level dSLR cameras), so your camera produces images around 5000 x 3500 pixels.  At that resolution, any print larger than about 6x8 inches means you have less than 600 PPI of original image information to work with.  Even printing a 6x8 inch print where you have about 600 PPI "worth of" image pixels to work with, you won't see much difference printing that at 1200 PPI because bumping the resolution that high means that 75% of the data in that 1200 PPI print is going to be interpolated.

So if you want to see a difference with overdrive, print small... not large.  Take a typical 16-18 megapixel photo that has a lot of sharp detail such as fine grass, tree bark, concrete texture, high contrast fenceposts with black/white detail like shadows, etc. and print it at 4x6 or (at most) 5x7.  Or maybe download a B/W resolution test chart (and again, print it small).  Then you should be able to see a difference under close examination of details.

Finally, unless you have millenial eyes, your eyes are likely to give out before 600 PPI so use some mild magnifiers (reading glasses) to see the difference.  The new feature is not so much about "blow you away" side-by-side comparisons but rather more geared toward making sure you get 100% out of your printer because, well... why not: produce the best prints possible and then you don't need to worry about how closely they'll be scrutinized later. 

Regards,
Mike

I've never heard of Ultraprint but in looking at the web page, I don't see that it is doing anything that Qimage doesn't do.  In fact, I don't know if Ultraprint uses a sharpening as sophisticated as DFS to avoid artifacts or if it automatically adjusts that sharpening based on original image resolution versus print size, and so on.  In Qimage, you only need to leave it set to "Fusion" interpolation and leave the print sharpening set at whatever level you normally use (I always use the default 5) and Qimage takes care of the rest.

Resolution is already limited by hardware and media and with today's printers, it comes down to the paper surface more than anything.  On the Ultraprint site, there appear to be scans of sections a little larger than 1 inch x 1 inch showing print detail.  I'm confident Qimage can do as good or better at those levels and it wouldn't require doing anything "carefully": just print.

I don't know if you've seen my own scans comparing normal 600 PPI printing versus overdrive where I show scans zoomed more than 4x more than those on the Ultraprint website (my scans are about 6mm across compared to the Ultraprint examples which are 28+mm across):

http://www.ddisoftware.com/qimage-u/tech-prt.htm

As a point of calibration, if you hold those normal/overdrive prints as close as you can focus with the unaided eye, you can only discern a difference if you are told where to look and what to look for and then, just barely.  The difference only becomes obvious when you examine the print with a 10x loupe.  So for normal photo prints, Qimage already goes beyond what the eye can see.  The Overdrive option was more for people doing specialized printing like lenticular prints that require precise line patterns and prints that are viewed under magnification.

Mike