Here are two problems with Mail when using with Gmail: 1) When, in the Mail Preferences, "Store sent messages on server" is selected, Mail is sent at exactly half of the speed. When you uncheck the "Store sent messages on server", then the mail is sent at full speed (very significant when there are attachments in the outgoing message). You'd think that the best way to solve the speed problem is to keep that box unchecked. Well you're kind of right. When "Store sent messages on server" is unchecked, it increases the speed but results in the "Sent mail" folder/Label showing up under the [Gmail] folder in Mail. When the user clicks on the "Sent mail" folder and see the entire list of mail you've sent, all you see is YOUR NAME, not the name of the PERSON YOU"RE SENDING IT TO. This design flaw or bug has been in Mail for years and I beg that people report it. (Note that if you are using Gmail and don't have this problem, that means your "Store sent messages on server" is checked and you're always sending mail at half the speed it should go, try it if you don't believe me) 2) PDF files in old messages are corrupt and can't be opened: When I look at a message that is several months old and open its PDF attachment, it can't be opened because it's corrupt! When I login to Gmail using the browser, those same attachments in those same messages are perfectly accessible. I can actually download those attachments into the browser and open it in Preview. Mail shouldn't have any problem opening up those attachments. I've tried deleting and creating accounts, rebuilding all mailboxes, deleting envelop indexes, researching optimal settings. You name it. Nothing solves these problems. The best I could do is report it to http://www.apple.com/feedback/mail.html And if you share my frustration, please send feedback and make Mail on ML even better!