Erm I’ve never owned the Ali one but I have ridden one. I own an Air 9C and have done for 2 years. My rigid A9c weighs a long 16lbs and I always say it rides like a road bike but with extended capability. It rides beautifully sat down or out of the saddle. I ride Exmoor, the Q’s and Dartmoor, so a variety of terrains some of which are quite rocky. The rigid fork can be a handful! But I wouldn’t change it as its primary function is XC race(off road triathlons mainly)
In my ,biased, view its one of the best racing mtb’s you can buy. This is my 30th year of racing off road so I have tried a few out.
In the broadest terms the carbon one feels “sharper”, but the number of compounding factors are huge. There is not a huge difference in weight.
Probably not worth the considerable extra dosh. But I would always go for the carbon for the slight benefit.