At some level, who cares? The point is that Adhearsion lets anyone write apps in Ruby. While it probably won't ever be completely abstracted from the platform it's running against, it's fairly close. A Ruby developer can certainly use Adhearsion without touching or understanding Asterisk.
How about something substantive? WHY is it superior? Or are you just trolling?
There's an effort going on to get Adhearsion running on FreeSwitch anyway.
I'm a huge FreeSWITCH fan, however I must agree with akalsey: WHY, exactly do you feel this way. I know why I do, but that's another story.