Update: Fusecompress has been completely unmaintained for quite a long time.
I have been using a fuse compressed file system for a very long time now. Space used to be a bit tight on my old laptop’s 60 GB hard drive, and the space savings haven’t been hurting at all. I have about 4 GB of documentation stored in text, html, and PDF files that I like to carry with me. I also like having it indexed by Gnome Tracker, which means it can't just be sitting in an archive.
I was previously using fuse-zip. It did its job very well and I really liked the fact that it was just mounting plain old standard zip files. It supported writes, but it only committed changes when the file system was unmounted. That was very inconvenient and it took quite a while to recompress 1-2 GB of data when I was only adding a few MB worth of files.
Now I have recently switched to fusecompress. The only thing I dislike is that it does not use a standard archive behind the scenes. I'm using bzip2 as the compression method and I had to tell fusecompress that it was, in fact, OK to attempt to compress PDF files.
Since fusecompress compresses individual files, I am not achieving quite as much compression as I was with fuse-zip, but it is quite close. I am don't mind trading a standard archive format for immediate commits of my writes.