I don't necessarily use push mail - i download my work email every 5mins and my personal email every 30 (6x more productive?) but i noticed that my mail wouldn't download according to schedule after i updated to 2.3.5 too.
Here's what i did:
I enabled background data.
that's it
That has worked for me for a few days now. My biggest concern with this fix was my battery life. As i type this, my phone has been actively downloading emails for two accounts for the past 8 hours and my battery is at 60%.
The thing that i did to save my battery life was to disable EVERYTHING that would drain my battery when i turned background data on.
I disabled automatic app updates (there's an option to do this universally in the play store). I turned off facebook notifications. I turned off groupon notifications.
I turned off weather, news, google, twitter...ALL THAT STUFF and it has worked.
...for me (i will come back if this solution fails - i don't expect it to)
hopefully it can work for you. I also turned off "refresh on open" in my email. Someone posted that as a fix on one of the at&t support pages. It didn't do anything for me by itself, but i have no intention of unchecking it to find out if it messes up my email receipts. Maybe after i'm done working for the day.
ALSO!
Is there any way to roll back to 2.3.4 +older version of sense?
jason:smokingsomb: <--i was just in mexico a few weeks ago. Not smoking cigars, but definitely wearing a fancy hat
edit: i have an htc inspire (att)