I have a mail server currently running qmail/vpopmail and I'll be moving to a Plesk based server. If I understand things correctly Plesk uses qmail, but not vpopmail. Currently mail is stored like so on my server
/home/vpopmail/domains/example.com/username/Maildir/new/

Can anyone tell me what the directories are like on Plesk?

Anyone moved from vpopmail to Plesk?

I've not tried migrating from vpopmail to qmail, so no idea if you're going to run into any difficulties with that!

The structure on Plesk/Qmail looks like:

/var/qmail/mailnames/example.com/username/Maildir/new