1. No Categories. Everyone manages email differently, and I like to use categories. With homemade categories like "Projects" and "Job Search" I can stay organised, search for past messages, and keep my inbox tidy with colour coding. But Mail doesn't have Categories. Instead, I had to download a third-party application called MailTags, which doesn't exactly solve the problem. MailTags never quite worked in conjunction with Mail's Rules option, much to my chagrin.

2. No Support for Hotmail. Hotmail (now Windows Live Mail) is a Microsoft property, and therefor a non-standard protocol. Philosophically, I feel this is abhorrent, but I've been using my old Hotmail account for years, and not having those messages in my email client is a massive handicap to my overall awareness and productivity. Until these two learn to cooperate, Mail will not feature Hotmail options. For this, a third-party solution also appears, in theory. I could never get it to work.

3. Rules suck. The rules don't work. They don't. I can create a huge list of possible scenarios for which to execute the rules, but somehow the don't seem to catch on. Half the time all I want to do is change the colour of the subject line, but I can't get Mail's Rules to work. Cultivating a Rule in Entourage is annoying, but the interface doesn't imply a limit due to the interface.

4. Problems with Servers. From day one with Mail, I've had trouble with the servers. At least half the time, any message won't send on the first try, requiring me to click "try again with selected server." No need for that. And certainly no explanation.