I just pushed the changes that add LZMA to (Open)Solaris
and also allow lofi(7D) to use LZMA as one of the
supported compression algorithms.

On an snv_111 machine, here's what you will see -

Usage: lofiadm -a file [ device ]
       [-c aes-128-cbc|aes-192-cbc|aes-256-cbc|des3-cbc|blowfish-cbc]
       [-e] [-k keyfile] [-T[token]:[manuf]:[serial]:key]
       lofiadm -d file | device
       lofiadm -C [gzip|gzip-6|gzip-9|lzma] [-s segment_size] file
       lofiadm -U file
       lofiadm [ file | device ]

So, if you take large'ish file and compress it with gzip
and lzma, the size difference is quite noticeable.

contraption# du -h solaris.orig
 2.2G   solaris.orig
contraption# lofiadm -C lzma solaris.orig
contraption# du -h solaris.orig
 555M   solaris.orig
contraption# lofiadm -U solaris.orig
contraption# lofiadm -C gzip solaris.orig
contraption# du -h solaris.orig
 702M   solaris.orig

With LZMA support now available for both userland and
kernel consumers, it should be very easy for other Solaris
utilities (zfs?) to provide support for it.