Owly I like my Sony 650 better than my Kobo Glo, but, my eyes need a lit screen for night reading.
So - I day read non-fiction using the 650 and night read fiction using the Glo.
It works for me.
I regard the Glo as a device in the making and if Kobo can get it's act together with better firmware then it may compete.
In the meantime I find the Glo sort of tacky compared to the feel and use of the 650.