[soulfuldog]

I seriously contemplated the original Kobo Aura instead of the PW but there were a few 'flaws' with the screen that were far bigger an issue for me than anything on the PW. I think the Glo HD and PW3 are probably fairly comparable, and if you were to stay with Kobo, you'd be far better hunting out a Glo HD than going for the Aura.

I personally like the Voyage for the way it makes the text appear almost printed on top of the screen, there's nothing in the specs for this (I think it's the glass screen compared to others using a plastic screen). I do see the slight light gradient with the light low at night, but that is the only negative I can find with it. Whether that's worth paying the extra money over a PW3 or Glo HD is completely subjective.

Stats don't tell you everything though, if you can have a look at any of them instore, it's worth doing so. Take your Glo with you and compare them. I wouldn't completely discount the Kobo Aura 2 either, sure its stats don't compare well with the Glo HD, but there's no feedback on how it looks yet, and just because it doesn't have the same PPI, it doesn't mean it will look awful.

The difference between a Pearl screen and Carta is that the latter has better contrast between the blacker text and lighter background than a Pearl screen, and it gives smoother page turns (quicker and smoother to refresh). How noticeable it is probably depends on how good your eyesight is though.

One thing to consider, you mention borrowing library books, isn't it only in the US that you can borrow library books for your Kindle, AFAIK Canada is like the UK in this respect, you need an epub ereader for library books?