I'm curious what sets this apart from the existing JuiceFS approach? JuiceFS is a commercial product, but with a foss community edition. It doesn't appear as a block device, but it does allow you superimpose an ext4-like filesystem complete with metadata etc. over S3 block storage (and others I believe). I've been using it for years and it's excellent.

Anyone know if this an improvement over the JuiceFS solution, and in what way(s)?