Although JFFS2 is extremely young, it is relatively mature, because it is developed from the excellent start given by the design of JFFS v1.
The frequency of bugs being reported has reached a fairly stable low level, and the majority of recent problems reported with JFFS2 have actually turned out to be errors in the physical flash drivers or with other parts of kernel code -- although sometimes this has highlighted an area where JFFS2 should be more fault-tolerant.
Both versions of JFFS are now in active use in a reasonable number of embedded systems, and JFFS2 has been included as a fundamental part of the ``Familiar'' distribution of Linux for the Compaq iPAQ handheld computer; replacing the read-only CRAMFS filesystem which was previously used on those devices.
The existence of a fully-functional writable file system for this class of device is an exciting development, and was absolutely essential to the progress of the Familiar distribution, allowing files to be overwritten individually without having to reset the device and use the bootloader to program a complete replacement CRAMFS.
Commercial support for JFFS2 is available from Red Hat, Inc., for customers wishing to use it in production systems with full backup from the developers.