They don't mention its differences with Namecoin, but Handshake (which .forever is a part of) does in its docs, which actually explains how this all works.

I haven't read all of Handshake's docs, so I'm not sure if .forever is any different than other domains using Handshake. That should go in its comparison table or FAQ.

It also doesn't say whether the domain can be pointed to things other than IP addresses, or whether it's more flexible than standard DNS records. Some entire ASNs have been blacklisted for no reason at all.