Comfortis is better than NexGard. Both Comfortis and NexGard are guaranteed to give a hundred perfect relief from fleas. Hence, you cannot separate these two here. However, NexGard takes around 24 hours to start working. That means it will take an entire day to relieve your pet of its fleas. Comfortis, on the other hand, shows results within just 30 minutes, and it has been proven in lab tests as well. So, Comfortis is the superior medication when compared to NexGard.