We migrate the Content and Metadata databases to our Test environment from Production, although I was recently asked if we should be moving the User Profile Service databases as well. I don't really find it useful to bring the three database, we do run CBA and migrate the external database that contains the logins although there seems to be little that we need from the Profile databases since we utilize more of the data from our own site. I don't have a good answer as to why we should or should not.
Has anyone migrated the databases from one environment to another? Are the User Profile databases as necessary if we are using Custom web parts that pull more data from our own DB? We do run synchronization but there isn't much that we use, except to keep the accounts in sync, so it seems like we could get away with not using these.