I somewhat care, in that I still want a desktop email client, but they all kinda suck and Thunderbird is no exception. It's slow and the GUI is rather flaky (and subjectively rather messy).

Every new email client seems to be more interested in re-inventing email that providing a simple straight forward client for "old school" usage.

Currently I use Apples email client, not that I absolutely love it or don't think it could be better, it's just the least no nonsense client currently available.

Thunderbird fails to deliver, for me at least, the same feeling of a well designed powerful application that Firefox does in the browser space.