The default outbound algorithm out of the box is Lowest Latency, so traffic will always favor the connection with the lowest latency. With our custom outbound policy routing though you can completely customize this to fir any environment:
http://www.peplink.com/knowledgebase/understanding-configuring-outbound-traffic-rules/
http://www.peplink.com/knowledgebase/video-how-to-create-outbound-rules/
Thanks!