I have not heard the SD3, but I have heard my fair share; including the IE80's. The FA's are no doubt the best all around earphone I've heard to date. I am a slight basshead, but I need clear mids and I like the sparkle; so really, I just need the full spectrum. These are nearly as clear as the PFE232's, but still VERY clear with good timbre. The mids are warm, soundstage is very large, the highs have a non-fatiguing sparkle, and the bass competes with any other basshead headphone I've had. It hits the sweet spot for me in every area-not to mention they're blue; my favorite color!
Also, the FA's are about the easiest set to drive. I have KEF M200's, and I still have to turn the volume down on my source when switching from them. Sure, they benefit from an amp, but they do EXTREMELY well without one. After my long adventure of buying and selling headphones, I nailed it down the the 1964ears and the FA's. FA's won without any question. They are fun and accurate at the same time.
I tend to prefer the silicone style tips; foam ones kinda look grungy after a white with me. I use the largest size Sony hybrids and they seem perfect to me!
Edited by MadMusicJunkie - 7/20/14 at 12:15am