[CentOS] Q. LUKS or ecryptfs-utils ?

I am now investigating encrypting our IMAP user spool files. Does anyone have experience with handling encrypted data stores using either or both of the subject methods and would care tio share their observations? Which is the preferred method (I know: it depends, but on what?)? What administrative pain does each cause?

Our IMAP host is a KVM guest so spinning up a duplicate and simply copying the data to an encrypted device or filesystem is not a very big deal. We can live with manually mounting the file system and providing a pass-phrase at boot. we are also looking into a semi-auto USB based solution to that issue.