I did have an interesting experience this year, but with Canon FL lenses which are 1960's era, more primitive coatings - FD glass seems like it's a bit more "modern" to me.
But anyway, for my commercial video projects I got my first 4K camera about a year ago and generally use my Nikkors on it. Noticed an FL/FD adapter that was affordable, and did some tests with my FLs - 19mm, 50mm and 100mm.
I was pretty freaking stunned by the beauty. Little idiosyncrasies in color rendering, overall a more muted palette but with a strange saturation to the cooler colors. Wide open, it seemed like "god's favorite diffusion filter", a bit of mistiness yet still sharp details where in-focus. Generally a sort of "rembrandt-ey" look.
Granted, this is one family of glass performing on one specific media (sensor or film), but I'm trying to come up with a beauty or music project to shoot entirely FL. Maybe not something the average consumer would notice (and not the best look for corporate work), but I think most shooters would pick up on it instantly. I've hear people go on and on and on about the "character" of various glass... this is the first time I've seen it so apparent (unless, like many people, by "character" you mean "Severely flawed image"...)