After reading a bunch of negative comments here, let me add a little on the bright side. I've been using Thunderbird for many years, currently both at home and at work to manage gmail accounts, pop at home, imap in the office. It works great for me, with a few annoyances but nothing serious.
As for the donations, Thunderbird seems to be somehow apart from Mozilla now, so I don't think much about specific org structure and will gladly donate.
Maybe on paper there're dozens of alternatives, but when I consider my specific requirements, I haven't found anything better, YMMV.
I use Thunderbird from the beginning when it was still named Firebird (I switched from Outlook Express). I think that it's a good product because it continues to do the job since more than 20 years. Me too I don't understand the negative comments. It's free (MPL license), it's packaged by Debian. All good. I don't care about Mozilla.
> Thunderbird seems to be somehow apart from Mozilla now
I don't think that's the case.
"Thunderbird is part of MZLA Technologies Corporation, a wholly owned subsidiary of Mozilla Foundation."
Thunderbirds sourcecode is literally part of the same mercury codebase as Firefox.
Thunderbird does have a very small team, and I think everyone that uses it should considering donating.
Likewise. Long time Thunderbird user since the original 1.0 days, for both work and personal use.
There's been a few ups and downs along the way but I've found it generally "just works" and gets out the way, which is exactly what I want in an email client.
I've tried almost every single email client I could find on Linux, and several on Windows (including Pegasus mail, if anyone remembers that), but always come back to Thunderbird.
I've been a regular donator to the project ever since they spun it out to MZLA Technologies Corporation.
I'm another appreciative long-term user. There are things about it that piss me off (especially the absence of a comfortable reading mode - with a quarter of an ordinary screen given over to ui and message headers) but it's been dependable over decades.
I've been using Thunderbird for decades, I've donated in the past, and am likely to donate again. With that out of the way, the lack of transparency as to what happens to my money kills the incentive to donate.
"How will my gift be used?"
"Thunderbird is the leading open source email and productivity app that is free for business and personal use. Your gift helps ensure it stays that way, and supports ongoing development."
Well that tells me exactly nothing. This might not be as big an issue if they were separate from Mozilla. To be concrete, and focusing only on the development of Firefox, there's now an AI chatbot in the sidebar. I think that's a good addition. However, when the only options are proprietary services, it's hard for me to see the point of Firefox. It would be easier to get out my credit card for Thunderbird if I didn't have those thoughts in the back of my mind. As it stands, my donation might be going to fund the Mozilla CEO's salary.