Centralized $HOME for roaming devices - sync instead of NFS?

For over a decade now I have been working in a full Debian environment in my small office (currently 1 server, 7 users, 3 desktops, 4 laptops). Authentication is based on Kerberos, user profiles are managed in LDAP, and $HOME is served to all of the clients over NFSv4 with the help of pam_mount or autofs. This setup is very much ok for desktop users working on the local lan. Two years ago, I started using the same setup for laptop users. The WiFi connection caused some additional sluggishness, and for sure once the users tried to use the laptop outside of the office, things got really slow. Optimizing $XDG_{CACHE,DATA,CONFIG}_HOME and looking into specific optimizations for Firefox on NFS made things a bit better. I'm now thinking of moving the $HOMES to the laptops+desktops. It is nice that a user can switch devices if one goes down, but that only happens once in a while. Sacrificing this flexibility for a faster day-to-day user experience seems like a good decision. If I could bi-directionally sync the local $HOME to the central server on startup and shutdown, there probably wouldn't be a tradeoff at all... - 'unison' seems like a good candidate for keeping the local $HOME in sync with a central copy, but it seems to require exact same versions between server and client, and that I cannot commit to. - 'lsyncd' seems to be a very good candidate, but I don't seem to find any user stories using the tool for their $HOME directories... - I even had a brief look at 'GlusterFS', but that seems like it's a non-trivial replacement. Anyone has any experience and maybe best practices to share? I don't mind a bit of experimenting, but I'm afraid I'm missing some obvious downsides to the above... Thx!