From what I have seen in stores, the Glo and the Paperwhite are both great devices.
I can tell first hand that the Kobo devices work very well with Calibre. As for Kindle, I can only assume that it's as good.
Between them, it's more with which one you feel more comfortable (graphic interface, dictionaries, highlights...). Not any device is perfect in itself, nor perfect for everyone. Not all of them do exactly the same thing, which is great since it leaves room to find the one fitted for one's needs
Regarding the Kobo bugs, I truly think they are more prone to be noticed by power users and readers switching between different makers.
In short, you can't go wrong with a Glo, a Paperwhite or the surprisingly nice Mini. In the end, it's how you feel with them.