There are four great things about Thunderbrid:
1) It's very easy to setup new accounts. If you use a well known email provider, like Gmail, Microsoft or Yahoo!, Thunderbird is able to automatically set up everything for you. All you need to do is click on the authorize button it shows you to enable Thunderbird to login to your account. Setting up an account on a private e-mail server is also very easy to do.
2) It's very easy to make backups: just copy your profile folder anywhere and you're good to go. This also makes it very easy to migrate your Thunderbird data to another machine.
3) It has a full-featured search function: You can search by keyword or phrase or by regular expressions, and you can limit your search to certain accounts, or search by participant in any conversation, among many other things.
4) It protects your privacy: media files in your mail are not downloaded and shown by default so you cannot be tracked when checking your email. This can be disabled on a per-mail, per-account or per-profile basis if you want to, however.
1) It can consume a considerable amount of hard drive space (my Thunderbird profile is about 10 GB after 4 years of use) since it downloads and caches any mail that you open. If you just check the headlines then it doesn't download anything, however.
2) There is no minimize-to-tray function. This was easy to fix in previous versions of Thunderbird with an extension (Thunderbird extensions are just like Firefox browser extensions), but the latest versions (from 2018 onwards) do not support any minimize-to-tray extension.
Just like it's sibling Firefox, Thunderbird requires a moderately modern machine to work. Other than that, it's both free, full-featured and easy to set-up so trying it out should not be any problem at all.
I use Thunderbird to handle all my email accounts, including my personal account Gmail account and several work related Gmail and institutional accounts. Thunderbird is compatible with SMTP, IMAP and POP3 e-mail servers so it works with any provider, like Google, Microsoft or even your own servers