In this list we have Timo and many other people very skilled in dovecot and mail related stuff. I read the considerations and I suppose they are right, but ... Also there are people like me that are lower profile sysadmins. Filtering mail isn't a problem, but, in my opinion, having the tag [Dovecot] in the subject is the better solution for "visual" filtering. I receive 2-300 mail / day in the inbox. Often I don't read a dovecot or postfix thread if the subject doesn't interest me, but sometime the tag [Dovecot], increase the appeal of others keyword ... Pheraps, mail filtered in folders are rarely read in real time. Usually I look at it in my spare time (very reduced), or when I search for a specific argoment. A couple of friends agree with me, so I am not the only ... ;-)
This is only our opinion as "low profile sysadmin",
Anyway, thanks to Timo and others for the great product and the support.
Regards, Paolo