with AR you would have overbridge in addition to analog engines with samples, or individual outs, meaning you can record 8 separate voices of 12 tracks and mix and process them to your liking in ableton, with OT you would be limited to 4 (you can utilize cues as outs right?) so mixing of everything would need to be in the box which is a point to consider.
from another pov, OT will handle loops much better with timestretch and slicing, not impossible with AR but would require substantial work to get things done.
they are too different to compare though, each has strengths and weaknesses that are not really comparable.
I own AR but I definitely see myself getting OT at some point for stereo samples, mangling, dj style transitions, etc.
of course each is capable of producing tracks on their own, or even albums.
btw check this guy doing amazing stuff with AR