The worst thing about Gmail on Android for me is that it doesn't deliver mails reliably. Sometimes when I open the web client on my computer I'm greeted by a list of unread emails, and almost immediately my phone fires of the notification for new mail, even though some of them can be several days old. This indicates that it's Google's servers that isn't sending the notification to my phone when mail arrives, but I consider them to be part of the same system and don't really care where the failure is.

Does anybody else have problems with mails not being delivered to their phones until hours or days after they've arrived in the inbox?