I have been trying a lot of the free email programs for quite some time now. And for my use, DreamMail is my personal choice.
Several years back, I purchased Incredimail. It was cute for some time, but way over priced. Then I began a search of the free ones.
Thunderbird was very nice in a lot of ways, but had a few quirks I did not like. One thing about TB that bugged me was when you compose a new
email and push the "to" tab, you have to type in a recipeint address. After the first letter or two, it would popup some choices for you to make.
Unlike most others I have tried, it would not popup address listing to choose. You have to start typing each recipient's name you wanted.
When I tried DreamMail, it was just the right fit for my use, and I have been using it now for about 2 months and I believe now I have found a "keeper".