Does anyone have any experience using their iPhone for their work email (with Exchange)? I just joined a small company and may be able to use the iPhone for emails instead of having them buy me a new Blackberry. Most curious about the following: 1) Impact on battery life - mine is already pretty bad with just a Gmail and Mobile Me accounts) and don't need it to get any worse; 2) Reliability - do emails actually come in as reliably as a Blackberry?; 3) Calendar - can you invite attendees in the company's address book? Thanks in advance!