I`m using Nextcloud since it was forked from Owncloud and tried out the Cozy-VM for a few minutes. According to the manual the setup of Cozy should be much easier (as long as there is no webserver already installed), since it installes and configures the webserver automatically. I also prefer its WebUI, but it has a major downside if you plan on setting up a private cloud for multiple users, since its basically not possible. In Nextcloud you can add users within seconds, while its almost impossible with Cozy. Also very interesting for some might be the possiblity to add online document editing in Nextcloud with Collabora Online (CODE), which is basically Libreoffice online.
I`m using Nextcloud since it was forked from Owncloud and tried out the Cozy-VM for a few minutes. According to the manual the setup of Cozy should be much easier (as long as there is no webserver already installed), since it installes and configures the webserver automatically. I also prefer its WebUI, but it has a major downside if you plan on setting up a private cloud for multiple users, since its basically not possible. In Nextcloud you can add users within seconds, while its almost impossible with Cozy. Also very interesting for some might be the possiblity to add online document editing in Nextcloud with Collabora Online (CODE), which is basically Libreoffice online.