Edward Shishkin released Reiser4 for the Linux 3.15.1 kernel last weekend. Besides being ported to the kernel interface changes for Linux 3.15, there's also two bug-fixes for the out-of-tree file-system. Most of the Reiser4 activity these days continues to just be porting to new kernel versions and bug-fixing. Edward is down to being one of the only main developers left and there's expected to be no effort to mainline the controversial file-system without the support of a major Linux ISV/IHV.
The Linux 3.15 Reiser4 patch can be downloaded from SourceForge. Likely for Linux 3.17 I'll do another large comparison of the many different Linux file-system options on HDD/SSDs, besides my usual Btrfs, EXT4, XFS, and F2FS testing I do each kernel cycle.