I never had the FD 1.4, I have a 1.8 unit that is absolutely brilliant, and a Rokkor MC 1.4 which is just fantastic. I know the Canons a little bit as I have the FL 55/1.2, FL 85/1.8, and have had the FL 50/1.8. My observation is that while they are not as nice looking as other legacies, the FD's are optically hard to beat. My all have a metal feel and handle very nicely.
The MC Rokkor 1.4 is a very special animal on its own. Wide open it has a special softness with a "glow", but stopped down to F2 it's painfully sharp, with gorgeous color and contrast, and lovely bokeh. Plus the handling of the focusing ring is almost unmatched, save for the Takumar lenses.
So as Kevin stated "better" is gonna be totally a matter of personal preference, and nobody can decide in your place what is the most important.
After testing countless 50ish lenses I now have found my favorite one, the one that has made me wanna stop searching and just enjoy it, but it might be entirely different for someone else. That's the catch, most of those lenses are very good, and you have to decide for yourself...