This is a filesystem in development, so don't put any important data on it (for known bugs, see the release notes). The 0.5 release has no emphasis on speed, so please don't run any benchmarks on it and then deduce that ext2 over fuse has to be that slow.
A more efficient release is forthcoming...
This release supports all system calls, barring a few extra things (extended attributes, really large file support) that most people won't be using anyway.
The release notes are at https://sourceforge.net/project/shownotes.php?release_id=487432&group_id=189090