Joe - I don't use hushed and reverent tones regarding Thunderbird. It's just a very competent and full-featured email client. I don't do emails on the move, so that use of webmail isn't relevant. One thing that webmail won't let me do is move threads and emails from one mail account to another - you can't easily view two email accounts at once.

I monitor 6 email accounts - 2 groups of 3. Many people know me in more than one of these roles and some of them can't conceive of a person using more than one email address. So when they use the wrong address, I just move the email to the correct inbox and reply.

You can set Thunderbird to download emails (POP) or leave them on the server (IMAP). If you're using POP, you can choose the period after downloading to leave the email on the server. There are many other settings.

I find the most useful feature to be filters. I have one which moves any email containing 'casino' or 'online gaming' to the Junk folder, so it never reaches the Inbox.

I've used Thunderbird since 2005. I've tried a few other clients but none of them seemed any better to me.

Phil