The best e-mail client for Win 10?

Thunderbird from Mozilla (unlimited accounts, freeware)
eM Client (freeware with one (two?) account

Curious- I use Tbird on 2 PCs and have no problems with it. There may be better ones out there.

The Mail app is often described as limited- for example, I gather that there's no way of exporting email. How would you transfer mail/contacts/rules (does it support mail rules?) to another PC?

My experiences with Outlook Express (withdrawn) then Win Mail (withdrawn) I decided never again to rely on MS products for such things which might suddenly vanish or change radically. Hopefully that won't happen with the Mail App....

Consider a cheap Office licence which will include Outlook

---that's another MS email product ----

(Just joking- I'm sure it's fine as Office isn't going away, although there are quite a few threads on Outlook and pst files).

Agree with @dalchina, Microsoft doesn't do ANY good email clients ... a lot of forums wouldn't survive if it wasn't for users having MS Outlook problems. The reason for their popularity is simply because users don't know any different .. "it comes with Windows/Office so I must use it.".

I've come across a few instances of users with TBird problems, and every one of them has been down to the user - bad program settings, bad email account settings, etc. I have TBird on 5 devices at home (one with 6 accounts), and support as a volunteer an organisation that has 23 TBird installations, again some with multiple accounts.

I really don't have to provide much support ....

I've been using Outlook successfully for about 25 years.

I do not use it because I don't know any better. I use it because it does the job I want - it manages email, contacts, calendar & notes [and tasks but I don't use that].

This comparison chart might help you decide Compare eM Client with other email clients - eMClient

Denis