The thing is, for me, I'd guess using MSAA from the ATI control panel would cause the same performance impact. So it would be kind of pointless to use the inferior (though definitely excellent) MLAA when I can get better visual quality with the same performance impact from MSAA. But I'll have to do my own tests to figure out how the MLAA impacts my framerate before I can say anything for sure.
Also, just to mention, the NFAA shader was so great to me because I was able to stop using MSAA and get a bit of my framerate back, and while there was the blur factor and some remaining aliasing to deal with, NFAA was definitely good enough for me considering the performance boost I got switching from MSAA. And I'm someone who didn't use OBGE(v2) for the longest time because I thought I had to sacrifice MSAA in order to use it (which was wrong, and of course I was missing out on NFAA the whole time also); quality AA is a necessity for me, and NFAA did a pretty damn good job. It's just that now, having seen the crisp quality of MLAA, it will be kind of disappointing if I have to go back to NFAA because the performance hit is too much. Crossing my fingers...