I have both the Kobo Glo and the Kindle Paperwhite.
Here is my assessment
of my two units:
The Kindle is much faster.
The Kobo Glo has dicey firmware and (sometimes) will produce a screen that is only 1/2 or 3/4 full of text.
The light on the Kobo Glo is brighter - but very manageable.
I like the Kindle firmware much better.
Moving from mobi to epub is nothing - I use calibre.
The Kindle paperwhite is a bit heavier than the Kobo Glo.
The Kobo Glo can use an mini-SD card.
I have no need for a mini-SD card.
I prefer both units, and enjoy both units - for the added luxury of having some variety in my life.
In case someone here is forgetful, the comments are based upon my experiences with my two units. Your life-force may vary.
Don