While I don't shoot for "clients" and do not have a lot of need for a printed portfolio I do agree viewing an image in a larger format is almost always more impressive then a smaller format. I would caution however that apples to apples, size for size, the aesthetic qualities of digital display vs print brings up a long argued debate.
I love my prints but it's hard to ignor the benefits of digital display. A good monitor is able to display a larger gamut of color then traditional pigments and dyes. A print also needs good quality light to display it properly where as a LED display, like the iPads, is light additive and provides its own consistent and uniform backlight to the image. The old argument was that a print has a tactile quality that cannot be matched by digital display, and that for me is still holds true, but the iPad certainly closes that gap in a way.