I am the OP of this thread but since then I got myself a KOBO and my wife got a SONY, you can read my thoughts as I posted them in another thread.
https://www.mobileread.com/forums/showthread.php?t=83138
Short Version: If the upcoming firmware update for Kobo fixes some of the bigger issues, then combined with the larger screen and SD slot I believe the KOBO wins. But as of right now the Sony seems to have the "it just works" thing going for it.