More flexibility than Star Alliance depends on what you want to do. xONEx is great if you want to do some very weird routing and maximize the miles you are in the air. You can get 50,000+ miles itineraries with oneworld which you can't do with *A.
Especially a xONE6 will not be great value after June when you can only do 16 flights compared to 24 coupons on Star Alliance.
Which class are you booking? If economy, then this books into L class. For some carriers you will only get 25% or 50% of actual miles flown. On Star Alliance it books into a higher booking class which is another advantage. So as always: YMMV.