I tried it, and I pretty much agree with the OP. The quality is about the same as 4XMSAA and there is a noticeable performance increase in older cards. If you have a newer card, the increases will be less noticeable.

I also question the compatibility with older DX versions. It seems this technology was aimed at supporting DX11. Since installing the 300 series driver, I started getting some FFXIV crash errors that I never got before. I suspect it's because DX9 is less compatible with the newer drivers.