Many enterprise IoT application scenarios, such as connected cars, smart cities, and cloud-connected industrial plants require distributed MQTT brokers to achieve high scalability and availability. With a market of over 20 MQTT brokers, it is hard for software architects to make a good selection. Existing MQTT comparisons often include only non-distributed brokers, focus exclusively on performance, or are difficult to generalize. We compared three distributed MQTT brokers for performance, scalability, resilience, security, extensibility, and usability in an enterprise IoT scenario deployed to an edge gateway cluster. We found that EMQX provided the best performance (28K msg/s), while only HiveMQ showed no message loss in our test scenario. VerneMQ offers similar features as the other brokers but is fully available as open source. The paper includes decision guidance for software architects, listing six major decision points regarding MQTT brokers.