Lately I've been feeling rather disappointed by Evolution. I've been a long time user (7 years I think) and for the most part it works great. But it's that "most part" bit that really is starting to grind. The last few iterations that I've tried (whatever is bundled with Ubuntu Feisty, Gutsy, Intrepid and Jaunty) have all had a a few quirks, none of them the same of course, For instance, The Intrepid version had an annoying habit of leaving messages marked as unread, even after I, you know, read them. Made for an annoyance when filing messages away. Worse, many of the messages that Evolution said were read, weren't really marked as such on the server so sometimes messages would magically unread themselves.
So I decided to give KMail another shot. I tried it last year sometime I think it was and decided it just didn't cut the mustard. But I'm a few revs forward on KDE now so it was worth a try. Over the last few days I have found it to be less annoying and much snappier than Evolution so I am considering a permanent switch, but it too does have issues. One major oddity is that when I open up a new folder, the unread messages count will reset while the folder is rescanned. That's just crazy. I can see why in a way, but there's just no need for it. A second complaint is that there's no way to move to the next message without closing the currently open message and opening a new window (I turn off the preview pane).
On the other hand, KMail excels in a quite a few ways. Contact auto completion is much much (much!) faster. I like the idea of the "favorite folders", although to date I haven't made much use of it. I like the way it integrates with my Spam Assassin. It handles multiple identities perfectly (although the configuration is kind of spread out).
Of course the elephant in the room is Exchange support. It's a necessary evil at least at my company (better than Groupwise!). Evolution has an Exchange plugin which works via Outlook Web Access to give you all the features of Exchange in Linux. In theory anyway. While many features do work, not all are flawless. The address book doesn't work for me. My calendar doesn't seem to sync with the server calendar. I've had previous problems with server-side calendar reminders not working, although the version in Jaunty seems to work fine.
Is there anything better out there that I should take a look at? Exchange support would be great, but frankly I don't use all the extra features all that often and if I have to fire up Outlook (via terminal services) once a week, that's not a deal breaker. I would like it to be rock solid, though.