An easy to use and stable email client. Ever since I first tested it it has been my main method of collecting email, and if my provider didn't make it necessary to log in to the web mail gateway at intervals I would only use Tenfourbird.
Pros
Easy to set up filtering to separate work and personal email. Uncluttered user interface. Takes Thunderbird add-ons. Stable, I can't remember it crashing in years.
