i notced this as well, with both my gmail and live accts... i set my live acct to manual and manually synced the email for a few hours. then switched it back to every 15 min and its working fine now...
i also went in settings>accounts> and updated each email client...
i've done this and i'm still having the same problem with no notifications. i'm getting everything in the email just no notifications about it. weird...
my hotmail and gmail account have not been auto synching for a couple days now. Its frustrating, but i just periodically refresh them to get the new emails. I miss my push notifications
Ok it seems to be fixed I had to uninstall the gmail updates and cache it all out then start over and it seems to be fine now. Weird. I wonder what could have caused that to begin with?