There are so many different bikes out there and with so many models that you have to be inventive to get a review for the rarer ones.
There are reviews for other models, like the level R for example. I haven't looked to be certain, but I'm guessing that the XR is better equipped than the R, therefore it will offer benefits via improved suspension (probably). Take a look at those reviews and then compare spec. The level R seems to be a very good bike, the XR may be even better.