Restic has a single binary that takes care of everything. It feels more modern and seems to work really well. Never had any issue restoring from it.
Just one data point. Stick to whatever works for you. But important to test not only your backups, but also restores!
I've found duplicity to be a little simplistic and brittle. Purging old backups is also difficult, you basically have to make a full backup (i.e. non-incremental) before you can do that, which increases bandwidth and storage cost.
Restic looks great feature-wise, but still feels like the low-level component you'd use to build a backup system, not a backup system in itself. It's also pre-1.0.
GPG is a bit quirky but I do regularly check my backups and restores (if once every few months counts as regular).
It's brilliant, works like a charm on freebsd windows and a rpi with linux since over 2 years.