I have owned both, and use them for all mountain and some urban and light FR in Oregon. The XTs had a problematic pedal thread, never worked right, completely sheared out one day while changing pedals. Shimano refused to warrantee, so I helicoiled them and put 'em on my girlfriend's bike. And then I got myself a set of Atlas cranks. No problems with them, and I know RF stands behind their products.