Wow, lots of nice replies already!
I was on the fence with Voyage anyway, but I guess I can safely say that it wouldn't do much for me if the Kobo + KOReader combo beats it.
As far as the Inkpad vs Kobo goes, I guess that my main dilemma would be the screen quality vs software trade-off? From what I've read, I can also install KOReader for Pocketbook devices, so if push comes to shove and the original software proves to be inadequate, that might improve things? The few reviews I've seen seemed to praise PocketBooks' support of various formats and their overall package. However, I've read a few disappointed posts from folks that found the InkPad screen to be worse than the older KPW3, with poor contrast, and letters which got muddled after one or two page flips. Does InkPad have something like the bold feature on the Kobos, to make the letters darker or more prominent?
As far as the SD card issue goes, I'm honestly not sure. 8GB is still a lot of space, and it's not like I have only 100MB PDFs to use. I guess that a lot would depend on how willing I am to switch between books. I do have a bunch of CBRs and CBZs, but somehow I haven't even considered them. Now that I think of it, it would be a boon to be able to read them, but are comics at all readable even on an 8-inch screen?
(Even on a monitor, I'm sort of partial to not scrolling or zooming in.) If not, then I guess that's just one reason less to stick to the notion an SD card. If expandable memory is all that's keeping me from a superior 8-inch screen and superior software, then I'll find a way around it.
It'd be awesome if any InkPad user could chime in, there's just so little reliable information. Basically, from what little that I have seen, there seems to be potential in the InkPad's software, but I have no idea if that potential is worth the obvious trade-offs.