There seems to be an issue with the 808 in that push email no longer works at least for the providers that need the Nokia mail service to enable push. The same account still works on the N8 (pushing)
There is a thread http://discussions.nokia.com/t5/Nseries-and-Symbian-Smartphones/808-Pureview-doesn-t-sync-email-automaticaly/td-p/1511126/highlight/false over at the Nokia support forums with more information.
Any chance that the good journalists at AAS could investigate this issue and and report on their findings as Nokia do not seem in the least interested in supporting their customers who have invested a considerable sum in their flagship device. Push email is listed as supported in the specification and also on the phone in the "info" section accessed from the mail set up page.