Hmm, I actually mostly stopped using Gmail, so I would not miss labels too much.
How about Postbox? I tried the latest Windows version under wine, only to learn that there is no calendar anymore (let alone caldav support) and the contacts do not sync at all. On the Mac they seem to integrate with system contacts and I could probably live with the system calendar.
Postbox is basically Thunderbird with system integrations, last I looked. I tend to find Gmail easier (and more pleasant) to use than Thunderbird, but I also haven't checked out Postbox for awhile to see how it's progressed.
It's sure to be more powerful, as is the Mailmate client mentioned earlier. I'm just not sure how "Maclike" the UIs will be.
How about Postbox? I tried the latest Windows version under wine, only to learn that there is no calendar anymore (let alone caldav support) and the contacts do not sync at all. On the Mac they seem to integrate with system contacts and I could probably live with the system calendar.