In the last two updates, MailMate has added functionality that is simply incredible, so it is time for me to write another review. If you have not tried MailMate in the last 2 months, it is also time to run it through its paces again in the light of this functionality.
I process a lot of email in a day with something at least 40 emails going out and 60 or so coming in (not counting spam or emails that I don't wish to read). Since I like a clean inbox, and I like to organize what I see coming in, that volume of mail could be very time consuming. However, with MailMate I am able to read and organize my email and keep a clean inbox with little effort and without the time-consuming hassle of moving emails to folders. This is possible because MailMate has added Tagging, and because its search functionality and its extremely smart SmartMailboxes. Some email goes with a particular project, which I tag with the project name; email which is critical but which can't be immediately answered gets a tag of 'critical' (and a tag of its project name, if it goes with a project); email which I've responded to but which I will need to move along further after I receive a reply back is tagged 'followup' (and a project tag, if relevant). Once the email is tagged, I archive it and it is no longer in the Inbox. Tagging is very quick (perhaps a keystroke) as is removing an old tag and adding a new one.
Emails are now categorized by some tag of relevance and some tag of what level of reply is needed. I have a smart mailbox for Critical mail and Followup mail, and for some important projects. MailMate can organize the mail within a smart mailbox by any criteria by which you can search: header items, tags, dates, subjects, contacts, the mailer used to sent the message..., the list is almost endless. So, when I look into my Critical smart mailbox I can see all the critical mail organized within folders by Project. I can have another Critical smart mailbox which is organized inside by what day or what month the email arrived (some things are more critical than others ;-) ). So if I can put some organization behind the smart mailbox with essentially no effort.
The search capability is amazing due to the ability to search by all those same items as mentioned above, as well as the nest the searches. It is next to impossible to lose any email if you remember anything about it at all.
Viewing your emails is also very convenient. There are a number of layouts available, and it is possible to write your own layouts as well. My favorite is "Correspondence" in which while you're reading an email you can see (in another pane) a header each for any other email correspondence with the sender. Another layout that I use sometimes shows at a glance the relationship between each email in a thread (which was a reply to which).
I don't know what others use, but I now have any functionality that I used in other email clients, and then some. [That is not to say that MailMate has every functionality of Mail (for instance), but I am sure that it has some that Mail does not] Within MailMate, it is possible to write using markup language, and not only that but it has a WYSIWYG view pane below so that you can see how it will be seen by the people reading the email. It is also easy to place pictures inline in your emails (drag-and-drop while writing as a MarkUp email). [Drag-and-drop also works from an email that you are reading to your desktop.] After writing your email you can also set a time when the email will be sent.
I don't know what more I could ask it to do. I want for nothing, and I have a lot more time back since I left Mail almost 3 years ago: both because it is some much easier to use while keeping on top of your mail load, and because it is more spry in handling my 90,000 messages over 3 IMAP accounts. I am sure that I missed some items, but the review is too long already.
The developer is very responsive, and that is one of those things that can't be bought (except through a license fee to this developer :-) ).