I own a 09 Reign x1 and its great.
The frames are exactly the same in the two models just the parts are different. If you have a fortune to spend get the X0, but the X1 can do anything the X0 can.
I very happy with my X1 and it will take a long, long time for my ability to exceed the bikes capabilities. They are very smooth to ride, and feel great ride most tracks around. Ive even done a few XC races on mine and my team won a race. Even though it is pretty heavy for that use I managed to overtake a stack of Lycra guys on super light XC bikes. Though I almost died at the end of each lap, so don't get one to do XC racing on.
But for freeride uses it handles the tracks great. I just need to get better so I can take full advantage of this bikes ability.