I'm British and have lived and worked in Spain for several years. I continuously correspond in English with people from many countries. I find that emails written by people from non-English speaking countries commonly end with 'Best regards', while this valediction is uncommon in correspondence with native speakers.
The questions, answers and comments proposing the use of 'best regards' on this forum and other places from my Google search appear to be posted predominantly by people with non-English sounding usernames.
I have nothing against 'best regards', but my recommendation to advanced English users in non-English speaking countries who want their emails to look as 'native' as possible is to substitute 'best regards' with 'kind regards' or 'best wishes'. Is this a valid suggestion?
Best Answer
I frequently use 'Best Regards' ...
...and I am a native speaker of American English.
The following is my personal opinion, but I've been told I'm pretty smart. ;-)
Best Regards - I find to be just right for people you like, but don't know that well, as in, most co-workers, salespeople, vendors, etc.
Best Wishes - Too floral for my taste when dealing with business correspondents.
Kind Regards - Same as above.
Kind Wishes - The worst of both!
Another option, that I've started using over the last 5 years or so is Cheers, which strikes me as chiefly British, but I like the sound of it. If I know the person well, I might use that instead.
Additional thought:
When I revisited this answer, it occurred to me that I actually, almost always, end corporate correspondence with:
Thanks,
Jim
This is done just above the rule above my 'Signature' from MS Office, with my full name, title, etc.