I have the Canon 50/1.4 on the 5D and it's pretty good.
Light in weight and pretty sharp, though DOF is very shallow at large apertures (i.e. >F2), so must be careful. But colours not as vibrant as my L zoom lenses (i.e. the 24-105 & 16-35).
Suggest you should go down to one of the camera retail haunts and play with both lenses - I've come to the realisation that purchase of lens A vs lens B often boils down to personal preferences.
All the best!
MW