I think this is the best email client out there for PC. I have been using it for a while after Outlook (a RAM hog IHMO) and it took a little getting used to but worth it over the long haul.
Software made to make email easier. Thunderbird is a free email application that’s easy to set up and customize – and it’s loaded with great features!
Source: Thunderbird — Software made to make email easier. — Mozilla