I use them, but stock up on brake pads. You can get two pair for $7 (thats' two sets in one package). Of all the sets available, they're the easiest to change the pads on (if you have a LONG and short screw driver).
Why not go with the stock pads for the XL? The pink fiber/whatever ones?
Just curious. I bought the XL brake system because I don't care for steel brakes. Too much maintenance and wear for me to want to deal with. The XL disks aren't nearly as aggressive, but they slow it down pretty good.