XC bike frames are either hardtail or short travel, semi-active suspension designs. Long and low, XC bikes put the rider in a stretched out position. Best suited to gradual terrain, XC racing bikes are popular in areas without a lot of rocks and roots and among competitive riders.
If your idea of mountain biking is fitness and endurance you may want to consider a XC Racing bike. If you consider the best rider the one who made it to the top first, then your choice is made.