I found the EFO to sound brighter/clearer overall compared to AFO. To me the EFO sounds like an HD800 with more bass and a slightly smaller soundstage, which is right up my alley. The AFO seemed darker overall especially in upper treble with a smaller soundstage. Really you can only tell if it's worth it by listening for yourself. I still do own the Aeon closed and since I just got my EFO delivered two days ago, have been A/B'ing it extensively with my AFC and HD800. I'm still in the process of burning in the EFO (currently have about 30 hours of time on it, 90% of which is playing 90 db pink noise overnight while I sleep).
I will admit I didn"t spend a ton of time with the AFO, as I was mostly focused on the Utopia, LCD4, and EFO. The AFO immediately sounded murky to me, much like the AFC, Eikon, EFC, etc. I guess I like a bit of hyped treble, and in that regard the EFO sounded a lot more like the LCD4 and Utopia.