Try printing with something other than Aperture. That way, if the problem still exists you know it's not Aperture (or a compatability issue), if it goes away then it is Aperture. It'll help you narrow down where the problem lies.
Also, how much is being cut off, what driver settings are you using, paper sizes, image size, etc etc.
Thanks for your input, as it pushed me to do some more testing.
It appears the problem lies within Aperture 3, as Preview prints fine. Previously, I'd been printing with Aperture's preset "standard" option, which left a minimum white border of about 1/4" on the left, but cropped the image about 3/8" on the right, thus leaving a white border of approximately 5/8" on the right. By increasing the border size equally to about 3/4" equally on each side, the problem disappears, and I'm able to obtain the full image. I was testing this on Epson's Premium Semigloss 250 letter size, using Aperture's "standard" letter size setting, which may be the problem. I need to see if this problem exists with other "preset" paper sizes within Aperture. Interestingly, when selecting the standard letter size in Preview the border size ends up being 9/16".
Otherwise the driver seems to work quite well, as the "too dark" problem seems to have been resolved.