When I first read about the Windows 8 Storage Spaces feature, I thought, awesome, Linux LVM capabilities for Windows! More specifically, a combination of the multiple device (MD) management in the kernel and the logical volume manager (LVM).
But then I realized that I hadn't read anything about atomic snapshot capabilities, which is my favorite feature of LVM2 on Linux. Atomic snapshots make consistent hot backups trivial. Snapshots are the top reason I set up LVM on every Linux box I create. Without snapshots, Storage Spaces seems significantly less interesting.
Hopefully Storage Spaces will have atomic snapshot capability and they just aren't talking about it yet.