A carbon 29er on one hand or a Garmin on the other? These seem like really different wants with really different price points. I'm slightly confused. Are you already into mountain biking (because I vaguely recall you're new to cycling)? As Loraura pointed out, 29ers make better sense on some types of terrain than others. What kind of terrain will you be riding? Otherwise, those are both nice bikes--if they fit.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher