For efficient contact management, use Datavare Address Book Converter, which allows for the merging of vCard files while retaining all of the constituent details. You can group a number of vCard files, join instances of vCard files, and merge contacts within address books into a single list that's well mapped out. It works on all versions of vCard (2.1, 3.0, 4.0) and additionally works offline, so your data is secured. You can quickly batch merge VCF contacts as well as retain phone numbers, emails, addresses, photos and custom fields. You can also check for duplicates as well as review the final file before saving. You can find out more here:
