To me, the AR skied like a wide GS ski. It wanted to be on edge and could slice through crud easily. The AX skied more like a narrow all mountain ski.
The AR seemed to be happier carving whereas the AX seemed a bit more versatile regarding turn shapes and types. Perhaps it was just that the skis had different tunes?
I'd echo Seldom's observations. I have only skied the AX for a few runs at demo events, but spent a week on a pair of brand-new-out-of-the-wrapper ARs on vacation last year in Europe skiing mostly piste, but some boot-deep snow. The AX at 78mm 11.8m +- radius underfoot and the AR at 83mm 12.3m +- radius underfoot have different personalities. The AX feels like a resort-oriented, mostly frontside all-mountain high-performance, carving-oriented design with a good variety of turn behaviors, while the AR feels like a wider, stronger platform definitely smitten with drawing strongly-carved GS radius turns deeply into the hill at higher speeds than the AX. If there were cruddy conditions...I would use the AR as the rock-solid platform of choice to generate float when needed, but freight-train through chop without any deflection or deviation from trajectory. If I was in tighter, bumpier conditions, the AX would do the trick. Both skis are excellent...It's like deciding if you like East coast IPAs or West coast IPAs with your meal..... depends on the meal.