I like Thunderbird a lot and like that it's not a Microsoft program. BUT, I rarely need technical support for Thunderbird (maybe 1 or 2 times per year at most). I do like to speak to a LIVE person for technical support & not have to spend hours researching the problem to still not come up with a totally satisfactory solution half the time. Technical support by chat and/or emails is worthless, and takes more time (hours by chat & days by email) than an hour or less speaking to a knowledgeable tech support person. That's why I don't currently donate. That's the most important change needed for Thunderbird. Better integration with other apps (Google calendar for example, although Google needs to get its act together as well! I'm currently looking for a better calendar that integrates with my Android phone.) I think Thunderbird is a simpler, superior email program that needs to add a few tweaks to allow better user customization, and I think Mozilla could keep its fees significantly lower than that crappy Outlook (say 25% or less of their fees), and Mozilla would keep the vast majority of your current users.
