I had a subscription to MBUK back in the early 90's and what I found after a couple of years was that they basically just re-cycled the stories year-on-year, but with newer bikes!!
They used to cover racing a lot, but it certainly seems that there arent any mags that cover XC anymore, prolly cos there arent anywhere near as many XC races anymore :?
By far the most entertaining read I ever found was Mountain Bike Action (I think), which I believe was an American publication, about 2/3rds the size of MBUK, but thicker.