I plan on putting this in the garage on the concrete floor where my kids will be climbing a vertical rope above it in case they fall while climbing. Is this the best mat you have for this kind of activity?

Depending on the height that they will be climbing it would be safe to land on. The higher someone climbs the softer you would want the landing to be. You may be interested in one of our crash mats if they might fall in any position other than on their feet.