LVM snapshots are a dream; it's amazing to be able to just take a snapshot, do something risky (eg. yum update or delete something), and then if terrible things happen, just merge the snapshot & restart to go back where you started. It also makes taking consistent backups easier. LVM snapshots require some free space on the volume group, something which I rarely ever see in the countless servers I maintain which were installed by other admins; and it's not trivial to add free space later. I get the impression that not many people are aware of this feature in Linux.
I was hoping Red Hat would encourage this feature in RHEL7 by leaving some gigabytes free in the volume group during the automatic partitioning, but unfortunately it seems to have gone the other way; even during the manual partitioning, it minimizes the Volume Group size regardless of the available space on the drive, making it not possible to take snapshots. One has to click on "Modify" next to "Volume Group", set the "Size policy" to "As large as possible", and then click on Update Settings (forgetting the last step is easy, and it's weird that things like changing the filesystem type or mount point does not require clicking "Update Settings" and only the LVM part does).
I was just hoping Red Hat would encourage snapshots by leaving some space free during automatic partitioning, or even just make it easier to leave space in the VG. I suppose hoping for it to give a warning message (as it does when the swap partition is missing) during manual partitioning to leave some space in the VG for snapshots is a bit of a stretch, but I think this small (but I suppose, to some, obtrusive) change would really result in a whole lot more admins using snapshots, making their lives easier.