openSUSE 12.1 is the first distribution that allows the creation of btrfs partitions in the installer. It also comes with a nice tool called snapper for managing snapshots of systems.
SUSE released a few weeks ago SUSE Linux Enterprise 11 Service Pack 2 which supports btrfs now as a file system and thus it's not a technology preview anymore. The SUSE Linux Enterprise team has done a lot of testing of btrfs and fixed many bugs - and backported btrfs fixes from the upstream kernels into the Linux 3.0 kernel that is used in the SUSE Linux Enterprise 11 SP2. openSUSE 12.1 comes with the newer Linux 3.1 kernel and the SUSE Labs kernel engineers have also added the same fixes that have been added to the enterprise kernel to this openSUSE kernel.
The 3.1.9 kernel which was released for openSUSE early February contained all fixes at that time. Additional fixes have been added since then and will be in the next update. These fixes include stability fixes and handling of errors.
For those that want to have the current kernel - before it gets released -, you can grab the kernel compiled daily from the kernel git repository by the openSUSE Build Service from one of our mirrors.
The openSUSE kernel team has more information about Linux kernels for openSUSE on its own web site http://kernel.opensuse.org.
I'd like to thank especially David Sterba, Jeff Mahoney and Mark Fashesh for debugging btrfs issues, fixing them and for backporting all the btrfs fixes to the openSUSE kernel!