The biggest real world difference is they are tiny, look awesome and don't need any cables. I've really not noticed any shocking performance differences between them and a RAID0 setup or separate OS/Game SSD's, with windows 8 onwards boot times are pretty fast anyway so it's hard to justify an improvement there. Any form of transfer to the drive is limited by another interface and I really don't know where I would distinguish a read speed that fast in daily use but i'm sure there are applications. They are getting much better in terms of motherboard compatibility and just simplicity of installation.
As I started off, their biggest advantage which I can see is in ITX systems where they occupy no space and require no cable at all. The most storage I have in any system is 480GB hence the ability to have a rig with no 5.25", 3.5" or 2.5" drives seems like a monumental step in the right direction. In an ATX build with other drives already though, it's not helping much. If you do for a specific application however benefit from the read speed but not necessarily huge volume they are phenomenally simple to configure and far less troubling than trying to run a RAID array etc.
JR