This is a example of some of the mind bogglingly stupid things that linux people do.
What I find funny now is years ago people on this board, myself included, where bashing microsoft for taking known standards and extending them. It was called embrace and extend. Linux at the time was the banner for standards and doing things right.
Now we have a major distro changing from the standard filesystem, ext3/ext4, to what is technically a experimental file system and using as the default install. This is crap that give linux a bad name. Linux will never take the desktop with bone headed decisions such as this.
There is a reason to sick to the ext3/4 filesystem as the standard filesystem. Because it is the standard. Almost every filesystem tool in the linux world expects to be working with ext3/ext4. Sure you have special versions for vanity filesystems such as reiser and this one, but most tools expect ext3/ext4. There is nothing wrong with running a specialized filesystem specialized applications such as databases but not as your main default system. And certainly not a damn beta filesystem.
Of course we are not new to bone head decisions are we when it comes to standards. Like the gnome people deciding that the middle mouse button is no longer important. Something that has been standard in xwindows and unix since it crawled out of the data ooze that spawned it.