More often lately users ask for support because they experience horrendously slow performance. In almost all cases they run Liferea on ext4fs where sqlite, when used with a lot of small update operations doing a lot of fsync() calls, is quite slow. This is not a specific problem of sqlite though, it just is very visible with applications performing a lot of write access like Liferea does using sqlite.
The important difference in this aspect from ext4fs to ext3fs is that ext4fs comes with barriers enabled, which is a filesystem feature (optional in ext3fs) that tries to improves filesystem integrity. But this comes at a cost: depending on your application use case this might decrease filesystem throughput a lot, which is what many Liferea users experience.
A workaround is to disable the ext4fs barriers by adding "barrier=0" to the mount options in /etc/fstab and remount the partition.