Which is better for a traveler: shortening and combining prayers, or performing them in full at the mosque to gain the reward of congregational prayer?

There is no need for confusion, for shortening the prayer for a traveler is permissible. However, performing it in congregation is better and more preferable, in order to attain the reward of congregational prayer and to avoid the disagreement of those who made it obligatory during travel, even if that entails performing the prayer in full.