First and foremost, information on encrypted file systems and their relative merits and support is few and far between. It is a complicated topic and discussions about benefits of one over another can be convoluted and confusing.
TCFS and CFS are both encrypted file systems based on the NFS interface. TCFS is enabled as a kernel module and CFS is enabled at user level. My experience with CFS is that it can be very slow, but I can only speak to its use on Linux platforms, not BSD or Solaris. Unfortunately, I have not used TCFS so I can't provide a comparison between the two.
My personal preference for an encrypted file system is dm-crypt. It is a secure and modern solution that is well integrated into the Linux 2.6 kernel.
This was first published in November 2006