I read about Ubuntu considering it for 13.04 and I think compressing with XZ really makes a difference. When creating a tarball for Liferea 1.9.6 the following compression ratios can be achieved:
CompressionSizeExtract Tarball With
uncompressed 8,0MB
make dist 1,88MBtar zxf ...
make dist-bzip21,35MBtar jxf ...
make dist-zlma 1,16MBtar Jxf ...
make dist-xz 1,14MBtar Jxf ...
XZ as well as zlma is supported by automake starting with version 1.12. Also check here for an in-depth speed and efficiency comparison of the Linux compression zoo.