Ok, two updates to Diablo later and we still have the same problems with the E-mail app. I leave my unit on, and modest randomly, silently crashes. I get no new mail notifications, and trying to open the client receives no response until I reboot the unit. I've missed important e-mails this way. Worked without problem pre-Diablo.

On top of this, Often if I double click on an e-mail to open and read it, sometimes it just disappears