One thing that keeps me using Mulberry is its "Cabinets" feature. I use sieve filters to filter my mail on my two university accounts into a variety of mailboxes, depending on various criteria. I have a Mulberry cabinet that shows me just the mailboxes that are able to receive new mail, so I can see at a glance which mailboxes have new mail. Mail in some mailboxes I know I want to look at right away, whereas others can wait. When I use Thunderbird, I have to scroll through my MANY mailboxes to find which ones have new mail, and I find that rather inconvenient. I also have a cabinet that holds just those mailboxes that I want to synchronize with mailboxes on my computer. With IMAP, I don't have to download messages, but I have 18 mailboxes whose contents I want to save on my hard drive. Mulberry's Auto-Synchronize cabinet makes it very easy to do this. Yet another cabinet I use is Copy Messages To. It simply lists all the mailboxes in which I might want to move a message after reading it. I haven't found this "cabinet" functionality in other email clients. It's not the only reason I stay with Mulberry, but it's one that I really don't want to give up. If there are more modern email clients that do have a similar feature, I'd like to know about them.