Like you I have a PW pre-ordered, but have not real format loyalty (although I've been buying Kindle's lately). I find the Glo to be a nice looking device and am still considering it.
My biggest question I ask myself about the Kobo is about the firmware. It seems like everytime they release something there are bugs and it takes a long time to get them worked out after the fact. Note that is my perception based on posts I've seen here and talking to a few people I know that own Kobo devices and may not really be fact, just my perception. The other thing holding me back from the Kobo is every customer support interaction I've had with them (for books I've bought and for the Kobo Vox) were horrible experiences, so that give me pause.
One other thing, does anyone know if the Glo's light setup is like the one on the Nook Glowlight? From what I've read that's a bit fragile.